The Yankee bullpen has been experiencing some worrisome shakiness as of late, but the addition of David Aardsma, who closed during his time with the Seattle Mariners, should provide another link in the chain between the good parts and scary parts if he can return to his pre-Tommy John surgery form. In 2010 with Seattle, he managed to hold right-handers to a .138 average in 26 innings. Lefties batted .239 off him, so he at least represents an upgrade over Cody Eppley status ( .340 BAA) against them.
The happiest news, however, is the return of Brett Gardner, who has missed all but nine games in 2012. Even if he is not in a position where he is well enough to be starting games, the ability to put him in on defense in the late innings over Raul Ibanez or Andruw Jones may prove to be enough of a reason to have him around on its own. As far as we know, his role will mainly be as a pinch runner and defensive replacement, which is certainly a place he can make a huge difference for now.
To make room for the newly-healthy additions, the Yankees sent Steve Pearce and Justin Thomas packing. Neither move is terribly surprising, but the depth at first base did just take a bit of a hit while Mark Teixeira remains injured without Pearce. Justin Thomas failed to impress much of anyone in his limited time with the club since being called up from the minors. It would be very difficult to argue that he will be missed down the stretch.