As reported by Baseball America's Matt Eddy, who's really good at this sort of stuff, the Yankees have signed RHP Adam Miller and OFers Cole Garner and DeWayne Wise.
Miller finally got back on the mound in 2011, after missing the entirety of the 2009 and 2010 seasons. He spent most of his year with Double-A Akron, where he went 1-4 with a 6.27 ERA over 23 games and 33 innings. He allowed 43 hits (but no longballs) and had a ghastly WHIP of 1.79.
Garner, 27, made his major league debut this year, playing in four games with the Rockies. He got his first of two big league hits on July 8, a single off of John Lannan. He added a second hit six days later, an infield single off of former Yankees reliever LaTroy Hawkins.
Wise, besides saving Mark Buehrle's perfect game, has cobbled together a .219/.256/.373 line over 445 career major league games. Of his 22 career longballs, seven have come against past and present Yankees, including Carl Pavano (twice), CC Sabathia, Kerry Wood, Alfredo Aceves, Kyle Farnsworth and Jeff Weaver.
Of those three, I'd expect only Miller would see significant time with the Thunder this season.