Can Jorge possibly keep up his contact and swing rates?

Like all teams, the Yankees faced a number of questions heading into the 2010 season. Could they continue to perform in the face of even loftier expectations? Would their new acquisitions adequately replace the departed? Can the veterans keep up their production? This last question concerned me most, particularly at two positions, shortstop and catcher. The Yankees have enjoyed advantages at those two spots over the past decade-plus. To see production erode there would run down the lineup. Thankfully, both Jorge Posada and Derek Jeter have opened the season with strong performances.

Of the two, Posada concerned me a bit more. Catchers typically slow down at Posada’s age, and while he’s done a good job of staving off Father Time to this point we know that can’t last forever. Early in the off-season, Bill James ran a study that examined the likelihood of a player’s performance declining in 2010. Of all players who accumulated 400 plate appearances in 2009, Jorge ranked as the most likely to decline. While age did play a factor, a number of performance issues did, too. For instance, Posada’s BB/K ratio was his lowest since 2001.

Thankfully, Posada has temporarily stopped these questions with his early season surge. In his 43 PA so far he has hit .378/.465/.730, a ridiculous .505 wOBA. Clearly he cannot maintain that throughout 2010. It does provide a positive sign, though, that he can continue producing at an elite level. Not only are his production numbers up, but so are his peripherals. His contact rate and walk rates are up, while his strikeout rate is down considerably. Even if these numbers come down (or up) a bit over the next five and a half months, Posada can still carve out an impressive season at age 38.

As we know, though, drawing conclusions form a sample as small as 43 PA can prove misleading. Anything can happen in two weeks, so we tend to back off on analysis of the first few weeks. Still, there are certain things we can glean from a sample only slightly larger than Jorge’s. From the Sabermetrics Library, we can start to see certain stats normalize at as few as 50 PA. Here’s the entire list:

• 50 PA: Swing%
• 100 PA: Contact Rate
• 150 PA: Strikeout Rate, Line Drive Rate, Pitches/PA
• 200 PA: Walk Rate, Ground Ball Rate, GB/FB
• 250 PA: Fly Ball Rate
• 300 PA: Home Run Rate, HR/FB
• 500 PA: OBP, SLG, OPS, 1B Rate, Popup Rate
• 550 PA: ISO

Posada’s Swing% currently sits at 42 percent, which more resembles his 2008 and 2009 seasons than his stellar 2007, when he was at 38.3 percent. That number could come down over his next seven PA, I suppose. Still, it seems odd to think that anyone’s Swing% would stabilize in as few as 50 PA. There’s research to back up the claim, but I’m still skeptical. I’d still expect Posada’s Swing% to resemble his 2002-2009 rate of 40.6 percent.

Two of Posada’s discipline stats which stand out are his Z-Contact and overall Contact rates. Z-Contact refers to pitches within the strike zone. Posada has yet to miss one of those pitches. He surely will, of course. Those numbers, according to Russell Carleton’s studies (linked at Sabermetrics Library), stabilize at 100 PA. Another two and a half weeks should give us a better indicator of whether Jorge will make contact at a rate closer to his 2007 mark of 82.5 percent, or more like his 2009 mark of 79.5 percent.

What I’ll really be looking at is where Jorge stands at around 200 PA. That’s when we’ll get a real idea of his strikeout and walk rates for the season. Again, Posada’s ranking in the Bill James study came in large part because his strikeout rate represented a seven-year high and his walk rate represented an eight-year low. So far in 2010 he has walked in 14 percent of his PA and has struck out in just 10.8 percent. Again, while we should expect these numbers to regress towards his career totals, they could still forecast a strong season.

As is quoted in the Sabermetics Library post, “In small sample sizes, a good scout is always better than stats.” I don’t think any scout, though, could find much to criticize in Jorge’s hot start. He won’t end the season with the numbers he has now — a .730 SLG is quite impossible for him. But it has been quite encouraging to see him get off to a hot start. If nothing else it set aside, at least temporarily, questions about his age. At best it forecasts yet another quality season from the seemingly ageless catcher.