Chip Kelly has been encouraged by the development of Tim Tebow since signing this offseason with the Philadelphia Eagles.

"I have seen an improvement from Tim since the day we got him in terms of his knowledge of what we're doing, understanding where everybody is," Kelly said, via the Delaware County Times. "There's a whole process, and for him what we have done is different than what he's done anywhere else.

"So in terms of learning our terminology and how we do things, I think each week you've seen an incremental bump in him, so we're excited to see where that takes him and it'll be a good competition as we get into August."

Sam Bradford is the presumptive start for the Eagles with Mark Sanchez as the backup.

When Tebow first arrived in Philadelphia, per the Allentown Morning Call, he "looked like a high school player." After two months in Kelly's offense, though, "he's improved steadily to the point where he's a legitimate threat to win the No. 3 job from Matt Barkley."

Sam Bradford and the Philadelphia Eagles have discussed an extension, but not progress has been made between the two sides.

With Bradford coming off a second ACL injury, the Eagles would likely want an incentive-laden deal they could get out from if the quarterback doesn't perform or gets injured again.

The Eagles could use the franchise tag on Bradford next offseason if he plays well.

The Philadelphia Eagles have released Evan Mathis.

Mathis had skipped the Eagles' offseason workouts in a contract dispute.

Mathis made two Pro Bowls since signing a five-year, $25 million contract with the Eagles in 2012.

Cary Williams didn't care for the system of Chip Kelly during his time playing for him with the Philadelphia Eagles.

Williams' gripe was that Kelly's revolutionary practices, which include a rigorous amount of conditioning, don't really work. He said his current team has the right idea and that players need to be better rested.

"We was talking about the fact that our conditioning and things like was going to kick in because we worked harder than everybody in the National Football League with the Chip Kelly thing," he told 710 ESPN in Seattle. "We got out there, we got our teeth kicked in. So all that conditioning didn't necessarily work. Preparation wasn't necessarily the greatest neither that week. When you're going up against teams that prepare well, practice well, coach well, it's difficult in games like that. I think towards the end of the year we were exhausted and we got outcoached the majority of the games."

Walter Thurmond is a veteran nickel corner the Philadelphia Eagles signed as a free agent, who is bidding to become the starter at safety opposite Malcolm Jenkins.

Of Thurmond, Kelly said: "Walt's done a really nice job. He's probably been our most productive guy in the secondary in terms of pass breakups and strips and things like that. He always seems to be around the ball, so he seems like he's fitting in there right now. But again, we still don't have pads on, we're still evaluating guys with helmets and shorts and T-shirts. But he's been very productive so far." 

Sam Bradford has consistently declined to offer a timeframe for when he will be 100 percent.

Bradford, the Philadelphia Eagles' presumptive starting quarterback, is recovering from his second left ACL tear in two years. He again threw 7-on-7 Monday, but did not take part in full-team work.

Bradford said he tore cartilage in neither of his injuries, both suffered with the St. Louis Rams. That fact makes the odds of a full recovery much more promising.

Asked about cartilage loss, he said doctors told him he was lucky. "It is an important factor," he said. "If there were more damage, you'd be looking at even a longer recovery time."

The Eagles acquired Bradford for Nick Foles this offseason.

"From the day I've been here we've talked about a progression," Bradford said, when asked why he can't throw 11-on-11 in noncontact OTAs; it doesn't seem all that different from 7-on-7. "Everything the past couple of weeks has gone exactly how we wanted it to, and I think we're going to kind of keep going with the plan."

Bradford said he has been stepping up activity 10 to 15 percent each week so far.

"That's a great question," Bradford said, the first time he was asked when he thinks he'll be 100 percent. "If I knew, I'd tell you guys. I really don't know."