Pittsburgh Steelers: Steelers running back Amos Zereoue, trying to beat Jerome Bettis for the starting job, injured his left ankle on the last play of practice Tuesday.

Coach Bill Cowher said he thinks the injury is a sprain and Zereoue will be examined Wednesday. Zereoue also missed two days of practice last week with a sore foot.

Zereoue stopped to catch a short pass that was thrown behind him during a scrimmage. He dived for the ball as defenders Chidi Iwuoma and Clark Haggans batted it into the air. Zereoue was helped by trainers, then carted off the field.

"An injury like that, a guy diving for the ball, you just hope he'll be fine," Bettis said. "It's not super serious to the point it will be a long-term situation. I hope."

Zereoue led the Steelers last season with 762 yards rushing. He has a chance to make Bettis a backup for the first time in his seven years with Pittsburgh.

Last season, his fourth with the Steelers, Zereoue started five regular-season games and two playoff games when Bettis was sidelined with injuries.

Denver Broncos: Just four days after he was released by the New England Patriots, cornerback Ben Kelly is back in the NFL, having agreed to terms on Tuesday with the Broncos. Kelly is believed to have signed a one-year contract.

The Broncos have been active in recent days in seeking to bolster the cornerback spot. Denver on Monday worked out a group of veterans corners that included Fred Vinson, Jimmy Hitchcock, Reggie Stephens, Robert Tate and LaVar Glover, but opted instead to sign Kelly, a three-year veteran.

Kelly, 24, has played in 13 regular-season games, principally as a "nickel" or "dime" defender, and has also returned kickoffs. New England released him last week, in part, because they had a logjam at cornerback, having used a pair of high-round choices on the position. The Patriots coaches also wanted to provide Kelly an opportunity to catch on with another team before clubs got too far into training camp.

A former Colorado standout, Kelly originally entered the league with Miami, as a No. 3 draft choice in 2000. He spent most of his rookie season on injured reserve and then was released the following year.

Dallas Cowboys: Cowboys linebackers coach Gary Gibbs returned to practice Tuesday from Oklahoma, where his wife and daughter were hospitalized after they were involved in an automobile accident.

The former Oklahoma coach, in his second season as a Dallas assistant coach, left camp Friday to tend to his family. He didn't want to talk about the accident Tuesday.

Gibbs' wife, Jeanne, and his 22-year-old daughter, Whitley, were hurt when the sport utility vehicle Jeanne Gibbs was driving swerved to avoid a bobcat and then overturned twice on Interstate 35. A 22-year-old family friend was killed and another passenger was injured.

Jeanne Gibbs had surgery at the University of Oklahoma Medical Center to repair broken bones and other injuries, and was in good condition Tuesday. Whitley Gibbs, who had cuts and bruises, has been released from the hospital.

Also: The Cowboys signed rookie fullback Erik Bickerstaff on Tuesday. Bickerstaff was expected to be Wisconsin's starting fullback last fall but didn't play because he had used up all of his eligibility, in part because school officials didn't monitor his academic progress.

Information from ESPN.com's Len Pasquarelli and The Associated Press was used in this report.