Are Mariano’s stats really in decline?


To date, Mariano Rivera has been pretty lights out for the Yankees. Not quite like he was last year; that was otherworldly. Still, save for a few rough outings, two of which came against the Rays, he’s locked down just about everything handed to him. Yet his numbers suggest that he’s lost a little something. Matthew Carruth of FanGraphs takes a look at what’s changed in 2009.

To sum up:

  • Mo has a 7.5% swinging strike rate, the lowest of his career.
  • He is throwing more pitches out of the zone.
  • More pitches thrown out of the zone + fewer swings and misses = unsustainable strikeout rate (which is right around where it was last year).
  • His home run rate is way up, but is unlikely to continue.
  • His groundball rate is at its lowest ever.

Carruth doesn’t make any projections based on this data, but he does wonder: “which regression, the strikeout and walk rates or the home run rate, [will influence] Rivera’s final line the most.” It depends, really, on how you choose to look at the data.

Yes, Mo has a 7.5 swinging strike percentage, which is the lowest of his career. That is indisputable. However, it seems that this might be overblown a bit. He started off in April getting 10 swinging strikes on 148 pitches (6.7%). In May he increased that to 14 for 180 (7.8%). That has gone down slightly in June, but remember that June includes his sick day against the Rays. He’s currently at 7.6%, but if you’re kind enough to excuse the Rays appearance, in which he generated zero swings and misses, he’s at 9.1%. If we can accept that his illness was the reason for his performance that day, this is an encouraging trend.

As to him throwing more pitches out of the zone this year, it’s not by a huge margin. From 2006 through 2008, Mo has thrown 69%, 70%, and 69% of his pitches for strikes. This year it is at 67%. Again, let’s look to that Rays game. Mo threw 21 pitches, 10 of which were strikes. Remove those and his strike percentage is up to 68%. Also, it’s not like Mo hasn’t gone seasons at a 67 or 68 percent strike rate. I don’t think this is a big deal at all, especially considering the anomalous Rays appearance.

This speaks to the strikeout rate argument. Again, if Mo isn’t really deviating from his career norms in strike percentage, and if his swing and miss percentage, outside of the Rays appearance, is on the rise, this doesn’t seem to be much of a concern. Maybe he won’t sustain the same rate as last year, but that’s again not a huge concern because last year’s was the highest of his career outside of 1996. In 2006, when he had a 1.80 ERA, he struck out 18.8 percent of hitters.

To the home run rate, I’m obviously going to agree with Carruth. He has allowed just one homer, a meaningless bomb in a blowout of the Orioles, since allowing back to back shots against the Rays on May 7. Mo has also allowed a homer on 15.2 percent of fly balls hit off him, which is more than double the career high (outside of ’95) he set last year.

The final bullet point might be troubling. Groundballs and strikeouts are a pitcher’s best friend. Mo is getting his strikeouts, but apparently his groundball rate is a tad on the low end. As in, his groundball to flyball ratio, not to be confused with groundout to airout ratio, is 0.90. Mo hasn’t been that low since his injury-shortened 2002 season, and hasn’t had a full season at that level since 2000. This does seem troubling. Not even removing the Rays outing helps mitigate that stat.

On the whole, we shouldn’t be concerned about Mo. He’s pitched damn well since getting shelled against Tampa Bay on May 7. Outside, of course, his sick day on June 6. If you’re willing to forgive that, he’s mostly on track. Even if you’re not, the trend is encouraging. The only real area where he’s slacking is in groundball outs, and that could be a real concern. We’ll have to see that one play out. Otherwise, we can sit back and enjoy the Mo.

Categories : Pitching


  1. On the flip side, though, is his velocity chart. I also wonder if we can remove bad games. At some point, that’s simply manipulating numbers to prove a point, and I know I’m guilty of it.

    He’s 39, and he’s coming off of a shoulder surgery. At some point, we will have to come to grips with the reality that Mo will decline and be gone in the not-too-distant. I’d rather not dwell on that aspect of Mo either though.

    • Notice, though, how I’m not suggesting we remove multiple games. Just one game, which seems like a complete anomaly.

      • That works for me. I’ve done that with Hughes’ numbers all season.

        • Glen L says:

          That’s how I ended up with a 3.92 GPA in college :D

          • Jesus says:

            I dunno though, i hate saying “if we remove this, or that” why not just replace it with his average outing?

            • Ed says:

              We want to remove outliers because an exceptionally bad pitching performance generally influences your stats far more than a good performance does. The huge influence means that what the rate stats show don’t give a good indication of the performance you can reasonably expect. The issue is even more pronounced when you’re talking about small samples, such as 1/3 of a season from a reliever.

              If you instead replace the outlier with an average outing, then all the rate stats stay the same as if you just removed the outing, making it pointless.

    • Joey H. says:

      Remove it all you want, you can’t remove them at the end of the year. Excuses excuses excuses. He hasn’t been great this year.

      • whozat says:

        Are you deliberately missing the point? We only care how he’s done insofar as it allows us to project how he’s going to do. Including an outing where he was vomiting all day and couldn’t do anything with his pitches only matters if you think he’s going to keep having outings like that. Since there’s no reason to think that, keeping that outing in the sample does nothing to help us project his performance going forward — and in fact actually makes our projections WORSE.

        • Joey H. says:

          No you guys are. Sometimes people need to step back and realize things aren’t as good as we wished for. The faster you realize that, the better. Dude is 39. That’s it.

          • whozat says:

            You didn’t even read any of my comment beyond the first sentence, did you?

            Are you saying that, because Mariano is 39, you expect him to have days during which he is vomiting repeatedly and trying to sleep it off in the trainer’s room until the 8th inning when he heads out to the bullpen to warm up? Because by including that game in the sample, that’s what you’re saying.

          • No, I think whozat has it right. In fact, he hit it on the head.

            Mo has had a few bad outings this year. He has done that EVERY year except last. Mo has been mostly awesome this year, and we have little reason to suspect he’ll fall off a cliff this year.

  2. Nady Nation says:

    Still extremely confident with Mo on the hill.

  3. Whizzo The Wize says:

    Perhaps Mo is just being nice to the new worms living under the new field?

    After the All-Star break and the worms are all comfy in their new home? Whizzo warns the worms to watch out!

    Mo will be fine. He’s Mo.

  4. A.D. says:

    Even if he loses something, he’s still one of the best in the business.

  5. Conan says:

    If he’s not the best closer right now, he’s still top 3 in the game.

  6. LiveFromNewYork says:

    It’s always a question as to what the eventual decline of Mo will look like. I hope he figures it out way ahead of everyone else and goes out on top. He deserves nothing but the best in his final years.

  7. Bo says:

    He would be better if he had a few guys in front of him who were better.

    • The Yankees would be better if they had a few guys in front of Mo who were better, but Rivera would be the same. There’s no logic behind your statement.

    • Chris says:

      I don’t think playing the infield in front of Mo would be a big help. They may even interfere with a few of his pitches.

    • I Remember Celerino Sanchez says:

      I hate to let stats and facts get in the way of your assertions, but, here are the games that Mo got hit this year, and how the bullpen did in front of him:

      April 24 v. Boston:
      Mo 1.1 4 2 2 0 3
      Preceded by
      Coke 1.1 0 0 0 1 0
      Albie 1 0 0 0 0 1

      May 7 v. Tampa
      Mo 0.2 2 2 2 0 1
      Preceded by
      Veras 2 1 1 1 2

      June 6 v. Tampa
      Mo 0.2 3 4 3 1 0
      Preceded by
      Nobody. CC went 8 innings.

      June 12 v. NYM
      Mo 1.1 1 1 1 1 2 (got the win anyway)
      Preceded by
      Tomko 0.2 3 4 4 2 1
      Robertson 1.1 1 1 1 1 3
      Coke 1.2 1 0 0 0 0

      I’m not buying it.

    • Bo and Axl are both firmly in the LaTroy Hawkins zone to me. Utterly ignored comments at the furthest reaches of the bullpen, seen only during hopeless blowouts.

      We haven’t technically DFA’d either of them yet, but they’re both walking corpses.

      On second thought, they’re not in the LaTroy Hawkins zone, they’re in the Kei Igawa zone.

  8. Glen L says:

    27.2 innings pitched this year

  9. Drew says:

    A couple months into the season, I’d have to imagine that his shoulder is nearly at full strength. In a month or two, if his numbers don’t resemble “typical Mo,” then I’ll be worried. It’s clear that his consistency with the cut movement is less than it’s been in the past. Also, the location is consistently perfect as we’ve been so used to.
    One thing I have noticed, and this is not to condemn JoPo, I noticed Cisco calls for the 2 seamer inside to righties, I rarely, if ever see Jorgie call for that same pitch. It seems to be effective and I’d like to see it more often.

  10. OmgZombies says:

    So if Mo is still inconsistent and blowing games/leads, who replaces him?I cant imagine the Yankees in the heat sepember rely on Mo if he cannot get the job done.

    • I Remember Celerino Sanchez says:

      Mo has a 1.084 WHIP. It’s hardly panic time.

      To put things in perspective, the three teams in the A.L. in the playoffs (besides the Yanks) if the season ended today have Papelbon at 1.321, Rodney at 1.346, and Francisco at 0.814 (but would you trade Mo for Francisco? I wouldn’t.).

      So I think the idea that Mo can’t get the job done is a little nuts right now.

      • OmgZombies says:

        That was purely hypothetical, I personally dont think Mo is done and nowhere near panicking. But if somehow Mo is not Mo, then you would have to look for a replacement as blasphemous as it sounds. I think Bruney would get the nod as hes done fantastic job as the set up-man this year.

  11. Ed says:

    The pitches out of the zone is insignificant. We’re talking about a 2% difference compared to the past few years. Assume Mo throws 10-20 pitches per outing, that’s a whopping 2 extra balls every 7 games or so. About 1 extra ball thrown each week.

    The home runs are also hard to get worked up over. Yeah, it’s a bad thing. But Mo typically gives up 3-4 home runs per season. Any increase is going to be a large increase from a percentage standpoint, especially when you’re talking partial seasons for a reliever.

    The 7.5% swing strike rate I’m a little curious about. There were no other data points mentioned for that stat, and on fangraphs I can’t find any stat that looks like it might be it, so I don’t know what to make of it. Is the 7.5% the difference between this year’s contact% (83.8%) and last year’s (76.3%) ? If so, it’s 5.2% higher than his career rate, which is interesting. 2.7% above his previous career high. He’s definitely slipping there.

    The ground ball / fly ball rate is possibly the most alarm. I’d imagine this means there’s less vertical movement on his pitches than before, which would explain the higher contact rate. Not a good thing if that’s the case.

  12. Joey H. says:

    The bottom line is, if you want to win the game don’t put Mariano in a tie game. Sorry but it’s happened WAY too many times so far. However having said that, he has one blown save all year. So he’s been pretty much lights out in that respect. It doesn’t have to be easy, it doesn’t have to be pretty, as long as you get the job done.

  13. Mike HC says:

    I don’t think you can just take out the game against the Rays. Who is to say that Mo didn’t pitch sick over the past couple of years as well? We would have to remove every sick game, whether good or bad. I do think that game was an anomaly though, and the more innings Mo accrues over the course of the year, the more the TB game gets negated.

    Mo is clearly in a decline stage of his career, as the past couple of years or so his velocity has been in the low 90′s. He is not the guy throwing upper 90’s fastballs by hitters anymore. Has he lost another MPH on the cutter this year, maybe. Either way, Mo is still an elite closer in this league, and I fully trust him.

  14. JP says:

    Joe Paw: The most important thing is that, even in an aging, potentially declining state, he is one of the 5 best relief pitchers in baseball.

    So I agree, that as an overarching rule, we don’t have to worry about Mo.

    As to your analysis, though, I think there’s alot of schmoozing and selecting in there, to try to paint a rosy picture.

    I prefer to accept that like any other baseball player, Mariano Rivera’s effectiveness is declining as he ages. I accept this as fact. The numbers, to me, are not up for debate as to whether they prove he’s declining. They are of interest to see if we can tell how, precisely, he’s declining.

    I don’t exempt him for his “sick” game. I’m sure he’s pitched sick before.

    There have been quite a few hard hit balls off him this year, and the number of hard grounders, vs. the usual cue shot foozles we’re used to seeing, also seems to be up. This would go along with a decline in his swing/miss rate.

    Does any of it mean anything significant? I don’t think so. There’s nothing really troubling in those numbers, other than they show he’s slowing down.

    From warp 6 to warp 3, I guess.

  15. Count Zero says:

    Where’s the broken bat%? That would be the clincher, right there.

    Seems like that cutter isn’t breaking as many bats this year, but that’s completely anecdotal based only on what I think I’m seeing in the appearances I’ve seen. :-)

  16. Joba-to-the-pen says:

    Why does this site care about MO.Like LoHud it believes relievers are failed pitchers and anyone can do it.Because you can’t get any pitcher to go 6 innings and give up four or five runs that takes talent.

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