A Case for Jhonny Peralta

Jhonny Peralta had his $7.25MM option turned down by the Tigers today and will instead pay a $250K buyout. While the team is still going to try to resign Peralta, we can take a look at what we can expect from the 28 year old shortstop. In the last 3 years he has maintained an average walk rate, taking a free pass around 8.0% of the time. He has struck out a bit more than average and his power has declined from 2008. Still, it is a thin market for shortstops and he might be valuable. I did some quick projection calculations to try and gauge his value.

Year BB% K% BABIP AVG OBP SLG wOBA 2008 7.2% 20.8% 0.312 0.276 0.331 0.473 0.347 2009 7.9% 23.0% 0.309 0.254 0.316 0.375 0.304 2010 8.6% 18.7% 0.275 0.249 0.311 0.392 0.309 Proj 8.1% 20.7% 0.298 0.261 0.321 0.412 0.321

That doesn’t seem so bad. With a line drive rate similar to 2010 (22.3%), his BABIP should have been significantly higher. Hopefully he can also get back to hitting the ball on the ground a bit more, rather than trying to lift the ball too much. HR/FB rate normalizes after 300 plate appearances and it certainly rose after he got out of Cleveland and got 242 PA’s. His numbers overall seemed to improve once he got to Detroit so maybe all that Peralta needed was a change of scenery. In any case, a .321 wOBA would be welcome production out of shortstop.

Peralta is not good defensively. UZR has him as being abyssmal (around -12), but other fielding metrics only have him as really bad. We can call him about a -8 defender after looking at all of the different advanced metrics.

It is pretty easy once we have these numbers to convert to a WAR scale. With his .321 wOBA, which happens to match up with this year’s average wOBA, his wRAA is +0. There is a +7.5 positional adjustment per 162 games at shortstop, but we can realistically only expect about 150 games so that’s +7 runs from that. He is docked -8 runs for his defense. Finally, replacement value is +20 runs per 600 PAs, which is a reasonable number to expect Peralta to reach next season. That gives +19 runs or +1.9 WAR.

Assuming he could reach this projection, Jhonny Peralta’s original option year with the Tigers isn’t that bad. I think that my method may be a bit on the optimistic side and may weigh regression too heavily (in which case I will need to tweak it). Giving Peralta a 2 year deal worth a total of around $8MM – $12MM, preferably based on incentives wouldn’t be bad at all. After doing this, I have decided that I would rather see Peralta with the Orioles in 2011 than Bill Hall. That said, the Tigers probably know how much he is worth and wouldn’t have declined his option if they weren’t certain they could resign him.