I just saw this in Carrie Muskat's blog.

"The Iowa Cubs also announced veteran Ramon Ortiz is joining the roster and will make his first start Monday night at Albuquerque.  The 37-year-old Ortiz made 16 appearances (eight starts) with the Dodgers last season and also made stops with Triple-A Buffalo in the Mets system and Triple-A Durham in the Rays system.  He was 3-5 with a 5.31 ERA in 28 games (14 starts) between the stops.  Ortiz has pitched for the Angels (2000-04), Reds(2005), Nationals (2006), Twins (2007), Rockies (2007), and the Dodgers (2010).  In 274 career games (212 starts) in the majors, he is 85-82 with a 4.93 ERA.  He also spent the 2008 season pitching for the Orix Buffaloes in Japan."

I'm guessing that he's insurance in case Russell struggles as a starter and Cashner and Wells are out longer than anticipated  A perfect combination for a AAA pitcher - old and bad.