The Redskins have acquired linebacker Hall Davis in a trade with the St. Louis Rams, the team announced on Monday.

In exchange for Hall, the Redskins sent a conditional draft pick to the Rams.

Davis, 6-5 and 272 pounds, was the Rams' fifth-round draft pick (149th overall) in last April's NFL Draft.

He is regarded as a strong pass rusher and he is expected to compete for playing time at outside linebacker in the Redskins' 3-4 defense.

Davis had been playing defensive end in the Rams' 4-3 defense.

He saw action in one of the Rams' three preseason games, the Aug. 21 game against the Cleveland Browns. He posted two sacks, one on Seneca Wallace and one on Colt McCoy.

Davis played college football at Louisiana-Lafayette.

The deal for Davis is separate from the Redskins' trade of tight end/fullback Dennis Morris to the Rams on Monday.

-- PORTIS OUT vs. ARIZONA

As expected, Clinton Portis will not play in the Redskins' preseason finale on Thursday night against the Arizona Cardinals.

Portis sat out practice on Monday with a sprained ankle. He continued to receive treatment, head coach Mike Shanahan said.

He suffered the injury early in the Redskins' 16-11 preseason win over the New York Jets.

Portis finishes preseason with nine rushes for 39 yards. He also caught one pass for five yards.

Shanahan is expected to give the Redskins' starters the Arizona game off, so Portis was unlikely to play on Thursday night anyway.