So I played around with (the invaluable) Brooks Baseball Brett Myers card, because I'm curious about his velocity in 2011. So let's look.
In April 2011, Myers threw his four-seamer 27% of the time for an average of 89.39mph.
May 2011: 28%, 89.06mph
June 2011: 19%, 89.25mph
July 2011: 25%, 88.95mph
August 2011: 31%, 90.35mph
September 2011: 17%, 89.36mph
How about 2010?
April 2010: 21%, 90.8mph
May 2010: 19%, 90.6mph
June 2010: 19%, 90.7mph
July 2010: 16%, 90.5mph
August 2010: 10%, 89.8mph
September 2010: 17%, 89.3mph
So Myers' fastball averaged over 90mph from April-July 2010, and has only enjoyed one month above 90mph avg (Aug 2011 - where he threw a higher percentage of four-seamers - by far) since July 2010.
This is more of a Public Service Announcement post than anything, other than that it doesn't look like Myers' velocity took a big hit from one month to the next - meaning it's not as though he went from throwing 94mph to throwing 87mph one month to the next. Do with this information what you will.