Margaret Bowles, Associated Press
Dallas Cowboys running back Felix Jones (28) runs past Tampa Bay Buccaneers defensive end Michael Bennett (71), defensive tackle Roy Miller (90) and defensive tackle Frank Okam (98) during the first half of an NFL football game on Saturday, Dec. 17, 2011, in Tampa, Fla.

IRVING, Texas — Cowboys running back Felix Jones missed practice Tuesday because of hamstring tightness. That left the Cowboys with two running backs who weren't even on an NFL roster a few weeks ago.

Sammy Morris, who made his season debut last week, split time at practice with Chauncey Washington, who signed with the Cowboys practice squad Nov. 30. Morris was cut at the end of training camp by New England while Washington was let go by St. Louis in August.

Coach Jason Garrett says he's hopeful that Jones will be able to practice some this week and be ready for Saturday's game against Philadelphia.

If not, Morris is the most logical choice to start since running backs DeMarco Murray and Phillip Tanner are on injured reserve.