Coach Jim Caldwell ruled him out for Friday's exhibition game at Oakland, but doesn't think Ansah will have much trouble catching on after a strong rookie season.
"He'll be able to catch up pretty quickly," Caldwell said. "But we'll take our time and there will be a progression to it."
A first-round selection in the 2013 draft, Ansah had eight sacks best among NFL rookies and forced a pair of fumbles while starting 12 of the 14 games he played.
The 6-foot-5, 278-pounder's speed got him noticed quickly last season and Caldwell said he can't wait to get him back.
"He's either going to collapse the pocket with his size or run around the other guy to create mismatches," the coach said. "And he can get us some sacks, too."
"He's a force."
Ansah's gradual return comes as tackle Nick Fairley continues to see most of his reps with the second-team defense. Caldwell said not to read anything into it, but Fairley's body language seems to indicate he's fallen out of favor.
His weight Fairley is listed at 308 pounds reportedly is the reason. Fairley, who's entering what could be his last season in Detroit after the team declined to exercise an option in his contract, ran past reporters when practice ended.
Veteran C.J. Mosley has taken Fairley's place on the first team alongside Ndamukong Suh in practice, but it's not certain the move will extend to Friday's game.
Mosley said he's simply stepping in when his number is called, but added he's hardly glad it came at what appears to be Fairley's expense.
"We're still teammates; you always support your teammates," he said.
Detroit begins the regular season Sept. 8 when the New York Giants visit for the Monday Night Football opener.
Notes • The competition to be the Lions' kicker got a new wrinkle Wednesday as Giorgio Tavecchio and Nate Freese took turns trying field goals while surrounded by a gauntlet of shouting players. Both were successful from 57 yards before missing tries of 62 and 67 yards. "It was unique," Tavecchio said. ... Wednesday was the last training camp practice open to the public.