Ronnie Brown's season has ended with an injury - again.

The Miami Dolphins' leading rusher was placed on injured reserve
Wednesday because of a right foot injury suffered in Sunday's
victory over Tampa Bay.

A fifth-year pro, Brown missed the final nine games of the 2007
season with a right knee injury.

The Dolphins had hoped Brown might be able to return this year
but made the roster move after he was examined by a specialist.
It's a big blow for a team that ranks fourth in the NFL in rushing
and 30th in passing.

The move was announced shortly after the Dolphins (4-5) departed
for Thursday's game against Carolina. Ricky Williams, the 2002 NFL
rushing champion, will replace Brown in the starting lineup.

Brown was on pace for the best year of his career with 648 yards
rushing and eight touchdowns, and he threw for another. He was the
triggerman in the wildcat, and it's uncertain how much the Dolphins
will use the package with Williams taking snaps.

Williams has rushed for 558 yards. He's coming off his first
100-yard game of the season and is averaging a career-best 5.3
yards per carry, but he's 32, and it's uncertain whether he can
handle a workhorse role.

The backup running back is now 2008 sixth-round draft pick Lex
Hilliard, who has yet to carry the ball in the NFL. Reserve running
back Patrick Cobbs was sidelined for the season by a knee injury
last month.

For Brown, the setback could be costly, because he's in the
final year of his rookie contract. Depending on when a collective
bargaining agreement is reached, he could become a free agent after
this season, and a second major injury in three seasons is sure to
hurt his market value.

Brown rebounded from his knee injury to start 13 games last
season to rush for 916 yards and 10 scores.

To replace him on the roster, the Dolphins signed safety Nate
Ness from the practice squad.