And you're asking, as I was: "Who?"
The scoop on Theo Epstein and Jed Hoyer's second waiver claim of this offseason from Carrie Muskat:
#Cubs claim RHP Donn Roach off waivers from Padres
— Carrie Muskat (@CarrieMuskat) November 12, 2014Roach started the season with the Padres and stayed with them until June 2, appearing in 16 games (one start). Heck, he even pitched against the Cubs once, May 23 in San Diego, the eighth inning of a game the Padres were winning 11-1 (no wonder I don't remember that one).
Roach, the Angels' third-round pick in 2010, posted a 4.75 ERA and 1.681 WHIP in those 16 appearances that covered 30⅓ innings. He walked 15 and struck out 17. He was worse after being demoted to Triple-A El Paso. There, he had a 5.24 ERA and 1.784 WHIP in 19 games (13 starts) covering 77⅓ innings. He had been acquired by the Padres in 2012 in the deal that sent Ernesto Frieri to Anaheim.
I don't see anything special in his record that would indicate he's anything more than roster filler. He'll turn 25 in December; it's an odd move considering the Cubs will want roster space to protect some players from the Rule 5 draft.
In case you don't remember the other waiver claim, the Cubs claimed Joseph Ortiz from the Rangers on October 6. The 40-man roster now stands at 38.