Rafael Rodriguez is a 25-year old relief pitcher who has spent most of the 2010 season pitching for Triple-A Salt Lake City.
He has served as their closer, posting fairly impressive numbers. He has a 5-3 record with 10 saves and a 3.04 ERA.
Despite pitching 50.1 innings, Rodriguez has only struck out 30 batters, which indicates to me that he is a pitcher that plays to contact.
There is not too much information out there regarding his skill set, but he pitched in Anaheim for 30 innings in the 2009 season (unfortunately, his ERA was 5.58 during that time).
I fully expect to see Rodriguez added to the 25-man roster along with Saunders. A move of this nature has already occurred this season (see: Sam Demel) and fortifying the pen was the main reason for this pickup.