With a 61% groundball rate (per Baseball Prospectus) and 198 Ks, Ubaldo Jimenez logged a SIERA of 3.67. His ERA was 3.47.
Jorge de la Rosa had a perfectly acceptable 51% GB% with 193 Ks, but logged a 4.38 ERA. BP's Siera was 3.55 though.
With a BABIP of .308 and a positive SIERA differential, de la Rosa appears poised to surprise. Ubaldo's BABIP in 2009 was .280. That, alongs with a negative SIERA differential in 2009, signals a worse season in 2010 for Ubaldo.