The Mets have upped the ante for the fourth-outfielder competition by signing Scott Hairston to a minor league contract. Ted Berg broke the news this morning on twitter and the tidbit has since been confirmed, but what the signing actually means is up in the air.
While many of Hairston's numbers have been deflated by playing in pitchers' parks most of his career, that much isn't likely to change in New York, and he's still managed to be the most powerful Hairston, a muted accomplishment given the state of the other baseballing Hairstons. What we can glean from his past is that he'll likely make the team because of his prowess hitting lefties and his ability to play every outfield position.
Hairston comes from a family steeped in hardball tradition. His grandfather Sammy Hairston got a cup of coffee in 1951, his father Jerry Hairston played to a .258/.362/.371 line over 2000 plate appearances between 1973 and 1989, and his brother Jerry Hairston, Jr. has been a .257/.325/.370 kind of hitter while playing all around the diamond for six teams in 13 seasons. In this context, Scott's .248/.315/.435 line comes out looking rosy.
Ignore the familial tendency to put up low batting averages, and you can see a glimpse of what he brings to the table, though. His .190 isolated slugging percentage is above average (that number trends to about .150 most years), and the fact that he managed 45 homers in 1009 plate appearances while playing for San Diego speaks to the same fact - he's got some pop. He even managed 24 in 528 PetCo plate appearances, kudos to him for muscling it out of the tough park.
Then again, he's a right-handed hitter, and it's not as tough to hit home runs in San Diego from that side. The park factor for home runs by a lefty is gruesome (59), but for a righty, just a tad harder than average (95). He'll fit right in at Citi, which had a 94 park factor for right-handed home runs last year.
Along with the power, you get mediocre plate discipline with Hairston. He walks a little less than average (7.1% career, most years the average is about 8.5%) and strikes out a little more than average (23.1% career, average most years is around 20%). But neither number is too far from the median, and his low batting averages are probably more the result of low BABIPs (.278 career) built on hitting the ball in the air more often than not (.72 GB/FB ratio, fly balls have lower BABIPs).
All of these statistics are better when Hairston is facing lefties. In 634 plate appearances against southpaws, Hairston has hit .278/.331/.498, compared to .227/.288/.402 against righties (in 1222 plate appearances). That's not quite statistically significant, but he's been better against lefties in every year of his career, so it certainly looks like a legitimate trend. For a team that had the fourth-worst wOBA in the National League against left-handed pitchers last year (.309), this is an interesting skill to own.
Defense is a plus for Hairston as well. In 125 games in center field, he's managed a positive UZR/150 (+7.7). On the other hand, he's probably not as good as that number suggests, given his UZR/150 in 275 games in the corner outfield (+6.6). In any case, he can play center in a pinch and is a boon on the corners, which can be important in a big ballpark.
Compared to Nick Evans, it's this track record and defense that puts him ahead in the battle for the fourth outfielder spot. There is a world in which both Evans and Hairston make this team - Evans could be the backup first baseman, for example - but this signing does make it slightly less likely.
In the end, though, it's about making this team better in any way possible. Getting a lefty-mashing backup that can play all three outfield positions on a cheap salary seems to qualify.