Marmol's average fastball velocity has dropped from over 94 mph the last two years to 91.7 mph in 2011.  His slider velocity has also dropped to 80.6 mph after being over 83 mph the last two years.  Generally, a 2 mph decrease is considered fairly substantial.  The decrease in velo doesn't seem to have affected his results, though it is something to monitor.  Opposing batters are making contact on 72% of his pitches this season, up from 61% in 2010, and are whiffing only 72% as much as last season.