Washington Redskins tight end Stephen Alexander resumed practicing yesterday and said his bruised lower back had improved significantly in recent days.

Alexander, who hurt his back during the Redskins' victory over the Carolina Panthers 12 days ago, said he received a cortisone injection on Tuesday. Alexander had pledged all along to play in Sunday's game at Arizona but Redskins officials, at least until yesterday, had been concerned that he might not last very long or be very effective. Alexander said he hopes he erased such doubts with the way he moved on the practice field yesterday.

"It's gotten a lot better," he said. "I've taken great strides the last few days. . . . Once I got it warmed up and was moving around, I couldn't even feel it. It'll be fine."

Guard Tre Johnson, who suffered a sprained knee ligament in the Carolina game, participated in a full practice yesterday after taking only about half the snaps Monday.

"It'll take all these days to get it right," Johnson said. "But I'm playing Sunday. That's what matters."

Barber Hangs Tough

First-year starting linebacker Shawn Barber has received plenty of criticism for his early-season play, but he said yesterday he accepts the situation.

"Even if I was a 17-year veteran, I'd feel like I was playing for my job," Barber said. "I put pressure on myself each and every week. I'm my worst critic. I'm willing to take criticism because it comes with the job."

Defensive coordinator Mike Nolan said he isn't giving up on Barber.

"It's unfair to drive a stake in a guy like that because there's a long way to go," Nolan said. "I'm not looking for a scapegoat." . . .

Veteran wide receiver Irving Fryar hopes to be more involved in the offense against the Cardinals. Fryar came out of retirement to sign with the Redskins during training camp, and only now is getting fully comfortable with the offense. The Redskins have been working on their three-wide-receiver packages to get Fryar on the field more with starters Michael Westbrook and Albert Connell.

"It's here," Fryar said. "It's comfortable. I feel good. I'm running great. The biggest thing for me was getting back in shape. Now I'm there, so it's all good from this point." . . .

Punter Matt Turk has blamed his early-season slump in part on some mechanical adjustments he made before the season. Special teams coach LeCharls McDaniel has urged him to return to his old style, but Turk said yesterday he now is trying to blend elements of his old and new mechanics.

"We're working together," said Turk. "We're on the same page. It's a mixture of both styles. It's a matter of me finding my groove."