Spears recorded 24 tackles, one tackle for loss and three pressures before injuring his calf early in the third quarter at Green Bay on Sunday night.
Owusu-Ansah, who was injured during the Jacksonville game on Oct. 31, saw action as the club's kickoff return man in the first seven games of the season. The rookie led the team with 25 kickoff returns for 543 yards (21.7 average) with a long return of 41 yards.
The Cowboys added two defensive linemen -- Jeremy Clark and Jimmy Saddler-McQueen -- to the active roster to shore up a position group that also will be without end Jason Hatcher for at least two more weeks and rookie Sean Lissemore for potentially four to six weeks, according to The Dallas Morning News. Hatcher has a strained groin muscle, while Lissemore sustained a high ankle sprain.
Clark, a four-year veteran, was released by the Arizona Cardinals on Sept. 3. He originally signed with the Philadelphia Eagles as a rookie free agent out of Alabama in 2007, where he spent his rookie season on their practice squad. Clark played for Sunday's opponent, the New York Giants, in 2008, recording four tackles in four games. In 2009, he spent time on both the Atlanta Falcons and Giants practice squads.
Saddler-McQueen went to training camp with the Cowboys after signing with the club on July 29 as a free agent out of Texas A&M Kingsville. He originally signed with the Chicago Bears after the 2010 NFL Draft and was released on July 21. Saddler-McQueen was released by Dallas on final roster cuts and signed to the St. Louis Rams practice squad.