Coach Brad Childress declined to divulge the specific injury, but said the fourth-year pro would be OK.
Jackson is in a competition with Sage Rosenfels for the starting quarterback position after Brett Favre decided not to come out of retirement and join the Vikings.
Mason’s back
Wide receiver Derrick Mason emerged from a brief retirement, returning to the Ravens less than three weeks after abruptly announcing the end to his 12-year career. The Ravens said Mason, 35, would be in uniform today . . . On the Browns’ first day of training camp, coach Eric Mangini said his team has no interest in signing Michael Vick, and he’s happy with quarterbacks Brady Quinn and Derek Anderson . . . Linebacker Jarvis Moss, the Broncos’ top draft pick in 2007, left camp amid reports he’s contemplating retirement.
Tough start for Wells
Beanie Wells
didn’t quite make it through his first practice with the Cardinals. The rookie running back, who earlier agreed to a five-year contract worth $11.8 million, rolled his left leg in a collision with another player late in the workout and was taken off on a cart. He was smiling as he left and the team said it was looking at his left ankle. The severity of the injury wasn’t known. Wells, the 31st overall pick, arrived at training camp at 224 pounds, down from the 246 he weighed after the draft . . . First-rounder Hakeem Nicks became the last of the Giants’ nine picks to reach a deal when the North Carolina receiver signed a five-year contract that will pay him a little less than $12.5 million. Nicks was the 29th pick overall . . . Other first-rounders agreeing to terms were Texans linebacker Brian Cushing (No. 15) and Titans receiver Kenny Britt (No. 30) . . . Pro Bowl nose tackle Kris Jenkins left Jets practice with a strained left calf, an injury not believed to be serious but likely to keep him sidelined a few days . . . The Bills signed defensive back Antwain Spann, who was cut by the Patriots last week after three seasons in New England.