Feb
10

Did David Robertson’s increased velocity lead to injury?

By

It was tough to not fall in love with David Robertson last season. For followers of Down on the Farm it was the realization of the potential we saw over the past few years. For the uninitiated it was his sneaky fastball and astronomical strikeout rate. Sure, his walk rate was at times frustrating — the game Al Aceves started in Minnesota comes immediately to mind — but his stuff made many wonder whether he could slide into a setup role and — maybe, possibly — eventually become a closer candidate.

In September we received the bad news: Robertson’s elbow was barking and he’d have to miss some time for it to heal. He did come back in time to warm up at the end of the month and make a playoff run, in which he allowed no runs on four hits and three walks in 5.1 innings. The only downside was that he struck out just three in that span, far, far below his season mark of around 13 per nine. Did something change for Robertson as a result of the injury?

In yesterday’s post about Joba’s diminished velocity, commenter tommiesmithjohncarlos linked to Robertson’s velocity chart. He called it sexy, but after clicking the link I became a bit more concerned. You can check it out here, or view it below. In 2008, during his brief call-up, his fastball velocity sat in the low 90s. It was the same upon his call-up in 2009, but as you can see his average fastball velocity climbed after the All-Star break. As it got up to the 93.5-94 range, we see a break in the action. That’s the September injury. So how big a concern is this?


Click for larger version

Correlation does not imply causation, so it’s difficult to say whether the increased velocity directly led to injury. The correlation certainly exists, though, so it raises some red flags. So does Robertson’s velocity upon return. Instead of averaging 93 or 94 mph, as you can see on the chart he was back down in the 92 mph range. That’s where he sat in the playoffs as well. From what I can tell, he never hit 94 after the elbow injury. This isn’t evidence that injury caused the velocity drop-off, of course. It could just as easily be that Robertson became a bit more cautious upon his return.

As Robertson’s velocity increased, he seemingly got better — not only in terms of strikeouts, but also in his walks. Again, the increase started after the first small break in the velocity plot, which represents the All-Star break. That gives us one full month of data, August. In that month he faced 45 batters, striking out 17 of them and walking just four. Just one hit a home run, and overall only three runners crossed the plate — two of which came when the team got blown out by Boston. Meanwhile, he had a ridiculously bloated BABIP, .494, though that hurts a lot less when you don’t allow that many balls in play.

Since there’s no clear conclusion on this case — I’m noting a trend rather than saying that X caused Y — I’d like to point out a few other awesome Robertson stats. In 2009 he faced 99 batters with the bases empty and 92 with runners on. In the latter category he absolutely dominated, striking out 33 to just 12 walks while allowing no home runs. He walked fewer batters with the bases empty, but also struck out fewer. He also did a damn good job of keeping the ball inside Yankee Stadium, allowing just one home run at home (84 batters faced). Finally, his poorest month earned run wise was July, in which he allowed seven runs to the 50 batters he faced. Yet his FIP that month was 3.82.

Thankfully, Robertson showed that he can get hitters out without a 93-94 mph fastball. It was a marvel to watch, and I hope he can still break it out in 2010. But if it had anything to do with his injury, at least we know he can survive without it. After all, he allowed just five runs to the 73 batters he faced from April through June, striking out 26 of them. Blazing fastball or not, I’m excited to see what Robertson can contribute this year.

Credit: AP Photo/Kathy Willens

Categories : Pitching

28 Comments»

  1. Charlie says:

    “He did come back in time to warm up at the end of the month and make a playoff run, in which he allowed no runs on four hits and three walks in 5.1 innings. The only downside was that he struck out just three in that span, far, far below his season mark of around 13 per nine.”

    I just don’t see how you can use that as evidence here. 5.1 innings is a ridiculously small sample size.

  2. Bonos says:

    There are other major leaguers around, too. Eiland said he’s worked with Dave Robertson, Alfredo Aceves and Mark Melancon. Robertson has “looked real good” the pitching coach said, and the changeup he started throwing last year is developing into a good pitch for him.

    “He got a feel for it pretty quickly, a little quicker than I thought he would and he took it out into games quicker and got some outs with it,” Eiland said. “It’s going to be a weapon for him against left-handed hitters, something soft, down and away, to complement that fastball that rides into them. It’ll be something that slows down the lefties’ bats, along with his curveball, and especially in our stadium, that will be good for him.”

    Eiland believes Robertson will be a big part of the 2010 bullpen – just like last year. “He really came on strong there toward the end,” Eiland said. “His velocity picked up, his command got better, his curveball got more consistent.”

    Read more: http://www.nydailynews.com/blo.....z0f6grGh4B

  3. Zack says:

    Here’s to DRob shutting up people saying we need joba in teh 8th!1! in 2010

  4. iYankees says:

    Awesome read, Joe. This is random, but I was actually gathering info to write up something similar a few weeks ago and didn’t, for whatever reason, actually do the post. But, I did find something interesting that might be relevant for you. I read in a Star-Ledger piece (below) that Dave Eiland actually tweaked Robertson’s delivery a bit, which helped him to throw harder (so, you can go a step further and wonder if Eiland’s changes contributed to the injury). I think the changes are significant since Robertson used to throw harder but toned down his delivery in order to throw more strikes. It’s an interesting issue and I’m looking forward to seeing how he throws this season.

    Here’s the stuff on the mechanics (towards the end):
    http://www.nj.com/yankees/inde....._robe.html

  5. Bo says:

    What Robertson just needs to do is keep his walk rate down. He put way too many baseurnners on last season. You cant pitch in the late innings doing that.

    • Accent Shallow says:

      This is a point I’d like to build on — despite a gaudy K-rate of 13/9, his strikeout to walk ratio was 2.7, because the walk rate was 4.7/9.

      Now, a 2.7 K/BB is pretty good (league average is about 2.0), but yeah, he’s either going to need to maintain a similarly crazy K-rate, or cut down on the walks.

      I’m not expecting him to maintain the K-rate while halving the walk rate. He’s not Mariano Rivera.

    • pete says:

      one thing i noticed last year was that he was ALWAYS right on the corners. This is why he had so many Ks and gave up so few HRs despite good but unspectacular stuff out of the pen. I think it’s ok to walk a few guys when you’re not giving up any hits or HRs.

  6. Steve H says:

    Where the injury was his elbow, I highly doubt it was related to increased velocity. Elbow injuries for the most part are attributed to throwing off-speed stuff. Picking up a few MPH on a fastball is highly unlikely to put much additional wear and tear on the elbow. With a shoulder injury there would be a chance, but again, we’d never truly know. I just hope D-Rob continues to progress, even some of the best pitchers in baseball walk a ton of guys when they are young. No SBGL, I didn’t just say that Robertson is or will become one of the best pitchers in baseball. CC/Mo/Maddux all had BB/9 north of 4 when younger. Hopefully Robertson can cut his BB/9 back into the high 2′s or 3′s, at which point you may be looking at a future closer.

  7. Jake H says:

    I also wonder if the increase in velocity is a change in fastball. It seemed that Robertson threw more of a 2 seamer then a 4 seamer. I say that because BA always said his fastball had good sink to it.

  8. Rose says:

    Correlation does not imply causation

    Wouldn’t something like this actually imply causation though? It just wouldn’t be certified or definite. When I think of the word “imply” I think of “suggest”. I may be entirely wrong on this…just might be a whole brevity thing.

    Either way, to say that velocity may have caused his injury could be just as arbitrary as any other uncommon event that may have happened. Not that you were saying this was the case, you actually stated that there was a chance it wasn’t…just thought I’d say that anyway though I guess. It’s early, give me a break here lol

  9. JohnC says:

    I really hope Melancon can step forward this year too. He started out very impressive, but was very erratic in his 2nd stint. He needs to get his control down pat in ST. We’ll need him this season.

  10. prime27 says:

    Velocity or not, he’s atleast show he can pitch under pressure. He probably had the biggest inning pitched of any yankee in the playoffs last year vs. Minnesota.

  11. Buffalo Fil says:

    That graph is a little ridiculous – let’s get a standard deviation in there. Also, given the accuracy of the MPH data are you really telling us there is a statistically significant difference between 92 and 94 MPH? How about a p value comparison.

  12. belg says:

    If D-rob develops a changeup I’d have illusions of grandeur and sugest that they try to develop him as a starting pitcher.

    FB-91-93
    Curve
    Changeup

    • Brett Gardner's Quadriceps says:

      Wow so now its Robertson To Teh RoTatuOn!!!!! while others want Joba to teh PEn!!!!!1!1!1!1!1!1!!1!1!1!1!111111

  13. [...] over at RAB wonders if Dave Robertson’s jump in velocity led to his ‘09 elbow [...]

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