if i was a dickhead who assumed you didnt know shit about sabr, this is what i would have posted
however, this is what im going to post, because he is actually slightly above average in defense at 1st base. http://www.fangraphs.com/leaders.aspx?pos=1b&stats=fld&lg=all&qual=300&type=1&season=2009&month=11
just to explain why the first set of statistics is not right (well it is right, but unreliable) you cannot effectively use many sabr stats over one year, but multiple years just to sort out any anomalies. if you go to overbay's career UZR by year, he has a few -5.0 seasons, but usually around 1.5 which is about his average (0 is average)
Flaw with that is UZR is the RBI of fielding stats. It should never be used as an end all be all metric. Did you hear about the Jason Bay controversy?
Speaking of controversies, WOW. Too bad for Galaragga. This incident is not over. Something drastic will happen (not necessarily the call being overturned).