Ramon A. Dominguez, aboard Little Mike, wins the Arlington Million horse race at Arlington Park, Saturday, Aug. 18, 2012, in Arlington Heights, Ill. (AP Photo/Jim Prisching)

Ramon A. Dominguez, top, aboard Little Mike, shouts as he heads to the winner's circle after winning the Arlington Million horse race at Arlington Park, Saturday, Aug. 18, 2012, in Arlington Heights, Ill. (AP Photo/Jim Prisching)

Ramon A. Dominguez, aboard Little Mike, celebrates as he wins the Arlington Million horse race at Arlington Park, Saturday, Aug. 18, 2012, in Arlington Heights, Ill. (AP Photo/Jim Prisching)

Little Mike, ridden by Ramon A. Dominguez, wins the Arlington Million horse race at Arlington Park, Saturday, Aug. 18, 2012, in Arlington Heights, Ill. (AP Photo/Jim Prisching)

FILE - In this Aug. 18, 2012, file photo, jockey Ramon A. Dominguez, aboard Little Mike, celebrates after they won the Arlington Million horse race at Arlington Park in Arlington Heights, Ill. The agent for Dominguez says doctors are optimistic the nation's leading rider will fully recover from a fractured skull. The jockey was injured on Firday, Jan. 2012,when his mount Convocation stumbled and fell during a race at Aqueduct race track in New York. Convocation bounced up, and did not appear seriously injured. (AP Photo/Jim Prisching, File)