Matt Klaassen of Fangraphs recently did studies that showed which numbers for both pitchers and hitters were the most predictive. For hitters, contact percentage proved to be the best predictor from season to season, while ground-balls were the best predictors for pitchers. If these statistics are the best predictors, then if a player has a significant change in them one way or the other, it is a bigger deal than if they have changes in those numbers than other numbers.

Michael Morse didn’t see a contact % drop in 2012 from previous years, but struggling Dustin Ackley’s actually improved by 2 %. Brendan Ryan saw a concerning drop of nearly 2%, which was a career low. Michael Saunders had a career high contact %, showing that his improvement was perhaps real. Weirdly, now former Mariner John Jaso’s contact percentage actually dropped. Kendrys Morales’ contact % predictably dropped when he came back from injury.

King Felix saw a small drop in GB % in 2012 from his career norms, as did Blake Beavan. It is hard to compare most of the Mariners pitchers since pitchers like Erasmo Ramirez, and Hisashi Iwakuma had no prior MLB experience. Former Mariner Jason Vargas saw a decent increase in ground-ball percentage last year, as did Kevin Millwood. Hector Noesi saw a big drop in ground-balls as a Mariner, while Charlie Furbush was basically the same in 2012.

The newest Mariner, Ronny Paulino, saw a drop in contact percentage in 2012, but he only played in 20 games. In 2011, he put together his best contact percentage of his career in a much bigger sample size. I have written about Paulino here before, but I wanted to see if we could quantify the difference between Jaso and Paulino. The question with Jaso was always defense, so let’s see if we can quantify the differences between the two. According to Matt Klaasen’s authoritative catcher rankings, Paulino was worth -.7 runs in 2012, while Jaso was worth -1.2. Of course, as we said above Paulino’s 2012 in the Majors was a small sample size, and you always want to look at multiple years anyway. In 2011, Paulino trended negatively again, worth -3.7 runs, but Jaso was worth -4.6 runs with the Rays. What about pitch framing? According to @Yonada’s (a Japanese Sabermatrician) work on pitch framing, Paulino has been worth positive 5 runs in framing since 2008, while Jaso has been worth -17 runs (for the record, Montero, who projects to catch a ton in 2013, was -4 runs in 2012). So defensively, this is the big difference between the two players. Just based off of empirical probability, we would expect Paulino to be worth ~ 6.2 runs more defensively than Jaso. Offensively, we can use the simple fantasy projections from MLB on the Bump (@mlbonthebump) since ZIPs isn’t out yet for the Mariners or Paulino. Paulino is projected to hit .264 with a 6.5 BB%  and 4 homers (1.5 %). Jaso on the other hand, is projected to hit .255, but with a 13.2 BB%, and 7 homers (2.1 %). So clearly, Jaso is projected to hit for more power, and get on base more than Paulino. Paulino is projected to get on base about 86 times, while Jaso is projected to get on base about 120 times. Even if we are extremely regressive and assume that just 1 in 4 of the times a hitter gets on base he scores, Jaso is still worth 8.5 runs more than Paulino, even without calculating power. If you assume each homer is worth about 2 runs, this brings Jaso to 14.5 runs better than Paulino in 2012 offensively. So if we combine the offense and defense (and assume that since they are both catchers, they are both bad baserunners, though Jaso is a much better baserunner according to speed score), Jaso is worth about 8.3 runs more than Paulino (obviously when the better projections come out, we will have a better idea).

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Of course, that Jaso is better than Paulino is no surprise, as Paulino will make a maximum of 1 million dollars (versus Jaso’s 2013 salary of 1.8 million). When I wrote up the trade, I did say that I think that Jaso is better than Morse, but just how much better? The big thing is team control. Paulino and Morse will both be free agents after the 2013 season while Jaso will be under Oakland Athletics’ team control for two extra years. So the combination of Morse and Paulino for 2013 would have to be better than 3 years of Jaso for the Mariners to win the trade from a value perspective. There is no rational reason to believe this. To go back to the MLB on the Bump projections, Morse is projected to hit .284 with with 24 homers and 29 walks in 525 plate appearances, or worth about 90 runs according to our regressed formula. This actually would put the combination of Morse and Paulino over (or at least close to) 3 years of Jaso. I don’t really believe that, but the projection is interesting, even if it’s main purpose is to just to play devil’s advocate.

Paulino does one of the things Jaso can’t do, he hits left-handed pitching. Of course, Jesus Montero had huge platoon splits in 2012, as he hit left-handers really well but really struggled against right-handers. Replacing Jaso with Paulino means that the Mariners do not really have someone to catch and hit right-handed pitchers (75% of pitchers) unless Jesus Montero improves in 2013.