04/17/2006 12:00AM

First Samurai off Derby trail


First Samurai, who finished fifth in Saturday's Blue Grass Stakes at Keeneland, is officially off the Kentucky Derby trail, his co-owner, Bruce Lunsford, told Daily Racing Form on Monday.

However, there are still so many 3-year-olds whose connections want to run in the 132nd Derby on May 6 that it appears graded stakes earnings will come into play. If more than 20 horses are entered in the Derby, the field is determined by earnings in graded stakes races.

That development makes this Saturday's $325,000 Coolmore Lexington Stakes at Keeneland a particularly crucial race for the likes of the undefeated Showing Up, who does not have any graded stakes money, and Sunriver, the third-place finisher in the Florida Derby, who currently is too low on the graded stakes list to make the Derby field.

The Lexington, along with the Withers Stakes on April 29 at Aqueduct, are the only two remaining graded stakes races for 3-year-olds preceding the Derby.

- additional reporting by Marty McGee