They say age is only a number. But it's much more than that right now for De'Vante Bausby. It's a reminder that his NFL career is on the clock.

It has not escaped his attention that, at 25, he is the oldest cornerback on the Eagles' spring roster. Given that he has played in only four NFL games since coming out of Division II Pittsburg (Kan.) State in 2015, that's not a good thing.

"I'm running out of time,'' Bausby acknowledged. "I need to put it all together. It's been four years. I feel like I've got everything right now, got all the information I need. Now I just need to put it together out there on the field.''

Bausby has spent the bulk of the last three years laboring on NFL practice squads, including most of last year with the Eagles'.

His play on the scout team caught the eye of defensive coordinator Jim Schwartz, who has been giving the 6-foot-1, 190-pounder some reps at slot corner with the Eagles' first-team defense during OTAs.

"He's a competitive player,'' Schwartz said earlier this week. "He's got good size, but his competitiveness stands out. He did a really good job for us on the scout teams last year. He was ready to play for us last year if need be.

"He did a great job not just on the practice field but in the meeting room, being up on the game plan. We were fortunate that we didn't have too many injuries there where he needed to go. But he was ready, and had the confidence of the coaching staff.''

One of the few position uncertainties for the Eagles heading into training camp this summer will be slot corner. Patrick Robinson did an outstanding job inside for the Super Bowl champs last season but was a free-agency casualty, signing a four-year, $20 million deal with New Orleans.

Schwartz has been rolling several players inside during OTAs, including Bausby, Jalen Mills, Sidney Jones, rookie fourth-rounder Avonte Maddox, and another 2017 practice-squadder, D.J. Killings.

"You're going to see a lot of different guys in there,'' Schwartz said. "We have a significant portion that will cross-train [play inside and outside]. We also have guys that will cross-train at safety and corner. We value versatility. That's a big part of the training this time of the year.''

This is the first time Bausby has played in the slot at the NFL level. He said he had slid inside in some sub-packages in college but was used strictly outside by his three NFL teams: the Eagles, Bears and Chiefs.

But his best shot at making the Eagles' season-opening roster could be inside. He made a couple of nice plays in the slot during Tuesday's practice, the only one of the Eagles' three OTAs this week that reporters were permitted to watch.

"After we lost P-Rob, I kind of knew they were going to be looking for a new nickel guy,'' Bausby said. "I wanted to get a shot at it.

"It's been good to be able to show them that I can do it with the first team. I'm just trying to be consistent and play the same way day in and day out.''

Bausby reached out to Robinson several times during the offseason for advice on playing inside.

"I just tried to soak up everything he said,'' Bausby said. "I would ask him, 'Why did you play it like this?' or 'Why did you play it like that?' I asked him a ton of questions. P-Rob is a good guy. He was very helpful.''

Bausby also spent a lot of time in the film room studying Robinson's impressive 2017 play.

"I did a lot of film watching,'' he said. "I just studied P-Rob. He mastered the inside last year. I watched his footwork and every little thing he did.''

Bausby was undrafted coming out of Pittsburg State, despite an impressive pro-day performance that included a "wind-aided'' 4.22-second 40-yard dash.

He signed with the Chiefs after the 2015 draft but broke his collarbone and was released. He'd been cut six times before joining the Eagles' practice squad last September, including four times by the Bears.

"It's definitely been a roller coaster,'' Bausby said. "It's been tough, real tough. But I've kept believing that better things are in store down the road. It's time for me to take advantage of the opportunity now.''

Bausby weighed just 177 pounds coming out of college. He has beefed up to 190. Schwartz likes his size and quickness.

"You didn't see him in training camp last year,'' Schwartz said of Bausby, who wasn't added to the Eagles' practice squad until after their first game.

"You will see him this year. I'm excited about him. We're all excited about the contributions he made to our team last year, and what he can do this year. He worked the offense hard last year [in practice]. I think those guys have respect for him, and I know our coaches have respect for him.''

Bausby said he "just tried to give the offense good looks day in and day out'' last year, "so that they could go out there on Sunday and excel.''

The practice squad isn't an option for Bausby this year. He has maxed out on practice-squad eligibility. If he doesn't make the Eagles' 53-man roster, he'll be cut.

"Alshon [Jeffery] used to tell me, 'Hey, Baus, you're way better than those guys' " on the other team, Bausby said. "That was good to hear. But it's time for me to prove it. Time for me to prove I belong.''