The Dallas Cowboys have replaced Bruce Carter in the starting lineup for Sunday’s game against the Denver Broncos not only for his poor play against the San Diego Chargers last week but also a disappointing and unacceptable lack of effort a source said.

Ernie Sims who replaced Carter in the second half against the Chargers will get the start at weakside linebacker and in the nickel packages against the Broncos.

Vice president Stephen Jones denied that the Cowboys questioned Carter’s effort against the Chargers.

Carter was admonished by the coaches for the effort that showed on film a source said.

No one questions the third-year linebacker’s heart and the coaches understand he was frustrated and lost confidence but they say the effort issues are not acceptable.

Carter is the team’s fastest and most athletic linebacker.

“They definitely got on me about it” Carter said. “I think just because I’m all over the field but there’s no excuse. I still have to play with a high tempo and just rally and get to the ball.”

Regarding his starting job Carter said: “I want to play. I don’t take nothing away from him. Ernie is my guy. I love him like a brother. I want to go out there just as much as he does. It’s out of my hands I’ll say that.”

The Cowboys have already replaced three other players in the starting lineup.

Carter joins cornerback Morris Claiborne who was supplanted by Orlando Scandrick; right guard Mackenzy Bernadeau who was replaced by Brian Waters; and safety Will Allen who was replaced by J.J. Wilcox.

Claiborne and Carter were first- and second-round picks respectively and considered cornerstone players for the future.

“Obviously we respect what the coaches feel like they need to do to get the most out of our players” Stephen Jones said. “We respect the decision they have made on who is going to start. We do need to have accountability if we are going to be better than we have done in the past. We don’t want to be a .500 team and to lose a game like we did [against the Chargers] drops us back to that level again.