After the Eagles finished practice on Thursday, the quarterbacks retreated to a far corner and worked on falling to the ground. They even tried tumbling. For such a glamorous position, it was not an especially graceful display. But considering that Sam Bradford's last two seasons ended with ominous falls, the training might be beneficial.

"I hope so," Bradford said, "or else we'd just look pretty foolish over there doing it."

Bradford has practiced four days without needing to pull back or manage his workload. The practices have intensified and he has not felt any problem with his left knee, which has undergone surgery twice.

"I think I feel better than what I was expecting," Bradford said. "I thought my knee would hold up, but I wasn't sure. I hadn't put it through four days of practices coming into camp. But the way my knee feels now, it feels great."

Coach Chip Kelly said Bradford is familiarizing himself with the speed and tempo of practices. When Kelly observes Bradford in practice and reviews film, he studies his comfort level with the offense. Kelly said there has been improvement each day. He also said he hasn't noticed a problem in Bradford's lower-body mechanics or weight distribution when the quarterback is stepping and throwing.

"We don't see him . . . favoring that leg at all," Kelly said.

Bradford tucked the ball during a practice Tuesday and showed that he's willing to scramble - although the defense was not allowed to hit him. That was the first time Kelly saw Bradford practice running with the ball and it prompted the coach to remind a questioner that Bradford is "a pretty athletic guy." He's a scratch golfer who played AAU basketball with Los Angeles Clippers star Blake Griffin.

Bradford first tore his anterior cruciate ligament in October 2013, when he was hit while he ran toward the sideline. He said running is part of the position, and he will not be reluctant to do it despite the knee injuries. But he also said he must be smart when he gets out of the pocket.

"You can't take that out of my game, but at the same time, it's not worth two extra yards," Bradford said.

So when Bradford sees a defender coming, he is learning to get to the ground. He will practice sliding during training camp. "It's been a long time since I played baseball, but we're going to try to re-create that here in a few days," Bradford said.

Kelly said in April that the Eagles were talking to Bradford about a contract extension. There have been conflicting reports in recent weeks - one saying he will play out the year, one saying he is in discussions for an extension.

"I'm not going to talk about contract stuff here," he said. "My focus is solely on football right now."

Barkley and Tebow

Kelly said there would be an open competition between Bradford and Mark Sanchez during training camp, but Bradford has taken the majority of the first-team quarterback snaps. A better competition is happening for the No. 3 spot, where Matt Barkley and Tim Tebow are trying to earn the role.

Barkley is the longest-tenured Eagles quarterback, but he has not been able to graduate to the No. 2 job since he was drafted in 2013. Tebow could offer more versatility at the third quarterback spot and could be used in ways other than a traditional quarterback.

"Tim obviously has a lot of skills that other quarterbacks don't have because of his ability to run the football, but we have not delved into any of that," Kelly said.

Barkley impressed Kelly this spring and understands the system entering his third year. The Eagles were patient with Barkley during a rookie season in which he was recovering from a shoulder injury, and they kept the former fourth-round pick as the No. 3 quarterback last season. Tebow presents his best competition yet.

"I thought [Barkley] had a really, really good April to June for us," Kelly said. "I thought there was a big improvement in terms of where he was."

Kelly said preseason games would offer the true evaluation for all four quarterbacks. That's when the hitting is live. They wear red, non-contact jerseys during training camp, so the only time they fall to the ground is when they do it intentionally after practice.

"It's not going to be like that when we get into those preseason games," Kelly said. "That will be the test for all those guys."