Dallas Cowboys outside linebacker Anthony Spencer admitted to not giving his best effort on a consistent basis last season.
Spencer told ESPN.com that he pinpointed the issue while reviewing film from last season. The four-year veteran watched himself making mistakes he couldn't explain.
"You can't mail days in in this league," Spencer said Thursday. "And I definitely found I was doing that last year."
Spencer, 27, said he would remedy the problem by "focusing more in practice."
The Cowboys gave up the second-most points of any team in the NFL in 2010. Despite his self-critique, Spencer had the second most combined tackles of his career (63), along with five sacks.