Sprained ankle will keep Pats' Wilson out against Colts

Free safety Eugene Wilson, arguably the New England Patriots' top coverage defender in their interior secondary, will not play in Sunday afternoon's game against the Indianapolis Colts because of a sprained ankle.

The Patriots on Saturday evening downgraded the status of Wilson, along with that of reserve linebacker Eric Alexander, a special teams contributor who has a knee injury. The ankle injury has limited Wilson's practice time in recent weeks.

Although Wilson has not started the past three games, his absence is still significant. Wilson would have provided New England a coverage option in defending Indianapolis tight end Dallas Clark, a key target for Peyton Manning in the middle of the field. Wilson is a onetime college cornerback who moved to safety as a rookie in 2003, but whose talents versus the pass lend flexibility to the New England coverage schemes.

Third-year veteran James Sanders, who started the first four games of the season at strong safety while Rodney Harrison was serving a league-imposed suspension, will start at the free safety spot. Since the return of Harrison to the lineup, the versatile Sanders has started the last three games at free safety.

The ankle injury that has plagued Wilson continues a string of injury problems for the five-year veteran. Wilson played in only four games in 2006 before going on injured reserve because of a chronic hamstring problem. In seven games this season, including five as the starting free safety, Wilson has 28 tackles and two passes defensed.

A former University of Illinois star and a second-round choice in the 2003 draft, Wilson has appeared in 58 career games. He has 251 tackles, nine interceptions and 27 passes defensed. But after registering four interceptions in each of his first two seasons, Wilson, 27, has just one since the end of the 2004 campaign, a falloff in part due to his injuries.

Alexander is a third-year veteran who has nine tackles in six games this year. In addition to his special teams responsibilities, Alexander is a solid backup linebacker.

The Pats on Saturday night also elevated safety Ray Ventrone from the practice squad to the active roster. Originally signed by New England as an undrafted college free agent in 2005, Ventrone has been on practice squads with the Pats and the New York Jets and played in the NFL Europa league in 2006. He has yet to appear in a regular-season game, and if he plays on Sunday, it will be on the special teams coverage units.

Len Pasquarelli is a senior NFL writer for ESPN.com.