ASHBURN, Va. — Redskins rookie receiver Devin Thomas probably will miss the team's first exhibition game after pulling his right hamstring in practice today.

Washington's top pick in this year's draft is expected to miss about two weeks of training camp. That timetable would keep Thomas out of the Aug. 3 Hall of Fame game against the Indianapolis Colts.

"We're going to see after two weeks how this thing looks. He may be ready in two weeks; it may be a few days later," Redskins coach Jim Zorn said. "We'll see how fast he can work himself into full speed."

Thomas was hurt while reaching over his head to catch a pass from quarterback Jason Campbell during 11-on-11 drills in the morning. Thomas was driven away on a cart, but he came out to watch Thursday's afternoon practice session.

"I was running a route, and the ball's in the air, and I felt something just grab at me," Thomas said. "It kind of locked up on me, just like a cramp, and I couldn't put any pressure on it."

He was drafted in the second round out of Michigan State, 34th overall, and signed a $4.83 million, four-year contract last week.

Thomas was optimistic that he will miss less than two weeks. Still, Zorn acknowledged there's a "learning curve" for any rookie.

"He's got to nurse this thing back a little bit, but it doesn't mean he can't learn, pay attention," Zorn said.

The team's top pick in 2007, safety LaRon Landry, was held out of both practices Thursday because of a strained left hamstring. He was hurt Wednesday, but isn't expected to miss more than a few days.

"I don't think it's that bad. I don't think it's as bad as Devin's is," Zorn said.

Also today, defensive end Chris Wilson strained his left calf muscle during drills.