Vasher has been working with the first team defense in Azumah's absence. In limited playing time as a rookie, Vasher led the team with five interceptions. The Bears felt confident enough that Vasher would continue to develop as the nickel back that they released R.W. McQuarters in May.
The coaching staff is getting an opportunity to evaluate Vasher in ways he had previously been untested.
"I think the continued improvement of Nathan Vasher is exciting to us, especially with Jerry out," Rivera said. "It's giving us a chance too see Nathan do a lot of things, not just play corner, but play nickel."
At 5-foot-10, 180 pounds Vasher will never be a dominating physical player. That didn't stop him from getting in the weight room this off-season and try to improve his strength.
"I think I'm in the best shape I've been in in a long time," Vasher said.
Rivera has been pleased with what he's seen from Vasher in run support, as well as when he's had a chance to go after the quarterback.
"I've been real happy when he's blitzed for us and I'm real us happy with him tackling. So I don't see a problem there," Rivera said.
Charles Tillman had to leave practice on Wednesday because of a tight back. While the problem is likely nothing serious, the Bears can't afford another injury at cornerback.
Tillman missed eight games last year because of a knee injury, but has looked to be in peak form during training camp.
In the absence of Tillman, Jerrell Pippens worked with the starting defense on Wednesday. He's competing for the fourth cornerback spot with Rashied Davis, who spent the previous four seasons in the Arena League. Both are long on talent and short on experience.
"Yes they do have a long way to go, but the best thing is to see them improve everyday," Rivera said. "Right now Jerrell has done a terrific job of improving everyday. I think Rashied Davis is showing us there's a lot of potential."
Pippens has the added benefit of versatility in his game. The converted college safety is learning how to play cornerback. If he makes the team he could fill two positions with one roster spot.
Mike Green made the reverse transition. He played cornerback in college and moved to safety when he entered the NFL. The Bears have been able to use him in both spots, which is a luxury when injuries hit.
At six-foot-2, 190 pounds Pippens has the size of a Tillman and it has showed in one aspect of his game.
"You talk about a corner that is an effective tackler, other than Charles and Jerry, I think Jerrell is a terrific tackler," Rivera said.
While Rivera has complimentary words for both players, it could come down to only one of them making the 53-man roster.
"I think as a group they're all competing and we've got some tough decisions ahead of us," Rivera said.