(Eds: With AP Photos.)

By CHRIS JENKINS

AP Sports Writer

GREEN BAY, Wis. (AP) - Packers rookie Randall Cobb turned some heads in practice, then made some plays during Green Bay's preseason loss at Cleveland on Saturday.

If Cobb can keep it up, the second-round draft pick out of Kentucky could challenge for playing time in what already was one of the NFL's most talented wide receiver groups. That's in addition to what most people expected him to do as a rookie - add some life to the Packers' long-suffering return game.

Cobb doesn't seem overwhelmed by his early success, and isn't surprised he was as productive in his first preseason game as he has been so far in practice.

That's what you're supposed to do,'' Cobb said.That's just something that's built into me, I want to go out in practice and get better each day, and then show how much I've gotten better in games.''

Cobb was the Packers' leading receiver Saturday, catching three passes for 60 yards. He also returned two kickoffs for 58 yards.

He was back at it in practice on Monday, again getting open to make a couple of nice catches in team drills.

Cobb certainly has to make the most of whatever chances come his way, given the talented group of veterans who also want the ball from Aaron Rodgers: Greg Jennings, tight end Jermichael Finley, Donald Driver, James Jones and Jordy Nelson.

As Cobb earns more attention from fans and media, his coaches are keeping him grounded. Packers coach Mike McCarthy says Cobb still has a lot to learn about playing in the NFL.

There's some things that he'll definitely do better, get more comfortable with,'' McCarthy said.I thought he was productive when he got his opportunities. I thought he looked pretty natural in the slot (receiver position), some of the things we asked him to do in the slot. I was comfortable with it. But he has to clean it up. He has some work to do, just like the other young guys do.''

One thing McCarthy wants to see is how Cobb handles game plans as they become more complex throughout the preseason.

Mentally, it wasn't a very challenging game plan for us Saturday,'' McCarthy said.That will increase some this week and even more next week. He needs to play, just like they all do.''

Cobb said he welcomes criticism from coaches because it ultimately will make him a better player.

I can take criticism,'' Cobb said.It doesn't bother me to take criticism. I use that as motivation. I use that as positive criticism, because all they're doing is trying to help me get better. So whenever I do make a mistake or I'm not doing what I'm supposed to, I take that criticism and I run with it.''

Cobb said he needed to work specifically on his run blocking, ability to read defenses and cut down on dropped passes - although he has shown in his short time with the team that he generally catches most balls thrown his way.

McCarthy said coaches will continue to pick apart Cobb's technique and fundamentals.

That's our job,'' McCarthy said.That's the way you make all players be accountable to improve.''

That's apparently just fine with Cobb, who is taking it as a sign that coaches are holding him to a higher standard.

That's what I expect from them,'' Cobb said.They're expecting me to hold myself to those things, too.''

NOTES: The Packers released LB Diyral Briggs. ... CB Sam Shields, who sat out Saturday with a hip injury, returned to practice Monday. ... Finley, who didn't play at Cleveland because of what McCarthy classified as a ``glute contusion,'' practiced Monday and said he will play against Arizona on Friday. ... McCarthy said RB James Starks (ankle) and WR/KR Shaky Smithson (shoulder) both tried to test their injuries before Monday's practice but neither was ready to go. McCarthy said he didn't have any update on WR Brett Swain's hamstring, and the timeline for the return of rookie RB Alex Green remains unclear.

Chris Jenkins can be reached at http:www.twitter.com/ByChrisJenkins