The ever-vigilant Ken Rosenthal says:
So, look out, Russ Canzler. There's an old-timer on your trail!
Funny thing about right-handed hitters. You often see players like Rivera, signed to serve as the short half of a platoon, referred to as "left-mashers." At one time, Rivera was certainly that: he's a career .285/.332/.488 hitter against southpaws, and as recently as 2009 he hit .333/.385/.645 against them in 156 plate appearances. That was then, but before we get to now, let's take a step back and talk about something that's probably obvious but is worth restating: over the last five years, the average AL right-handed hitter has hit .267/.337/.427 against left-handed pitching. That's as opposed to .257/.315/.407 against right-handed pitching. In other words, the typical right-handed hitter starts with a big advantage over his southpaw-pitching brethren. In order to be a true "lefty-masher," the right-handed hitter has to make an Olympic hurdle over the 764 OPS which is the birthright of anyone who happens to swing from his side of the plate. Cody Ross, now of the Diamondbacks, he does that -- he's a career .295/.373/.636 hitter against lefties. Jonny Gomes, who you will see face Boone Logan or Clay Rapada or Cesar Cabral once a game now that he's with the Red Sox, is a .284/.382/.512 hitter against lefties. NL MVP Buster Posey, a right-handed hitter, smacked a cool .433/.470/.793 against southpaws last year.
Looked at in the context of the players who really do mash lefties -- and at .324/.364/498 career against them, Matt Diaz is (assuming health) probably one -- Rivera doesn't look that special. In two of the last three seasons he hasn't done much with lefties at all, hitting .270/.329/.434 against them overall, while against right-handers he's hit just .243/.298/.368, which is pretty much the numerical equivalent of "Abandon hope, all ye who enter here." To continue with Dante, "Through Juan you pass into the city of woe; through Juan you pass into eternal pain."
But for an inexplicably strong 2009, when he punished lefties and somehow fooled the defensive metrics into thinking he was Superman in left field, Rivera has been replacement level or worse since 2006. The Yankees are just rounding up the usual suspects, so there's no need to get too exercised about his being given a chance, but really, these platoon options are from hunger.
...And I made it all the way through this post without mentioning the 2002 knee fracture in which he ran into a maintenance golf cart while shagging flies about two minutes after being called up. Whew!