Jarrett Bush has heard it all. He’s heard media members that have never played the game say he can’t cover. He’s heard couch-slouch fans say he’s not fast enough. He’s heard incessantly that he’s a special teams ace, a euphemism that indirectly denigrates his ability as a cornerback as much as it lauds his value as a special teamer.

Through it all, Bush has remained untiringly positive. He smiles broadly, answers questions earnestly and speaks with a buoyant confidence that belies the doubts of others. And now, after re-signing with the team in the offseason and two days before the Packers season opener against the 49ers, he’s preparing for the biggest role he’s had since being claimed off waivers by Green Bay as an undrafted free agent in 2006.

“I’m just trying to do my part now and play on this team,” Bush said Friday. “I want to take full advantage of my opportunities and make plays. Play my part. I’m part of this great defense.”

Exactly how big a part is still officially unknown. The Packers have yet to announce a starting right cornerback for Sunday’s game, though it will almost certainly be either the physical Bush or speedy Sam Shields. After frontrunner Davon House got hurt in the preseason opener and rookie Casey Hayward fell off, Bush and Shields have been locked in a competitive position battle for a couple of weeks.

But the 28-year-old Bush, who’s started just seven of 94 career games but entered training camp as the starter and finished the preseason as the starter, might be the stronger play against the powerful, run-heavy 49ers. It’s mostly a nominal title, since the Packers play so much three-cornerback nickel defense, but Bush certainly sounded like a starter on Friday.

“Definitely on the defensive side, my role has expanded,” he said. “But I’m going to keep doing what I’m doing and keep playing confident, and keep trying to strive for that No. 1 spot in the No. 1 takeaway defense.

“It’s a great feeling, the confidence [the Packers] have in me and I have the same confidence in myself to go out there and make plays. I’m not just being out there to just be out there. I’m out there to make plays, make tackles in the backfield and pick balls off.”

Coaches never stop praising him for his hustle, heart and physicality, and this year they’ve begun complimenting his improving coverage skills. Still, Bush insisted he will do whatever it takes, whether it be on his familiar special teams units or on the outside covering an elite wide receiver like San Francisco’s Randy Moss.

”Whatever I can do to help my team out,” he said, “whether that be on special teams helping [returner] Randall [Cobb] get in the end zone, making tackles on kickoff, where I am that’s where I’m going to play, and I’m going to be dominant at it.

“Whether it be defense, kickoff, punt return, I'm going to do it and play my heart out, because that's what I expect from my teammates and that's what they expect from me.”

House out: It was widely assumed House would not play against the 49ers, and on Friday coach Mike McCarthy made it official. House (shoulder) is one of three players out for Sunday’s game, joining ILB Jamari Lattimore (ankle) and RB James Starks (toe).

House was the leading candidate for the No. 2 cornerback job until he dislocated his shoulder in the first preseason game at San Diego. He just returned to practice this week and is wearing a restrictive brace to protect the shoulder that encumbers his movement. Though he said the harness “sucks” to wear, he had held out hope he’d be able to play in Week 1.

On Friday McCarthy said, “I think Davon did very well yesterday. It was good to see him in pads. It was his first time he was in pads since the injury. I really liked what I saw. He feels good. His evaluation this morning was good. But at the end of the day I didn’t think it was practical to put him out there. He’s a young player, he’s coming off that injury, so we’ll see how he is next week.

"I hope he feels better Monday. We’ll work him out extensively Sunday before the game because there is a conditioning element to this when players come off injuries, especially being a perimeter player. We’ll condition him Sunday. We’ll be in-house Monday, we won’t practice Monday, it’ll be all meetings. But we’ll practice Tuesday, so we’ll have more information then.”

Praise for Green: In other news involving promising but injury-riddled second-year players, McCarthy said running back Alex Green was ready to play Sunday, even though he did not participate in practice on Friday. The Packers have been cautious easing back Green, who tore his ACL last October and has seen limited snaps.

"Alex has done very well in training camp," McCarthy said. "[We] had him on a rep count through the training camp, starting slow, he probably did more than what we had hoped for, so that’s good. I think he’s definitely ready to go. This is a long week of practice, of preparing for this game. So we felt it was smart to rest him today."

Green (knee) is officially listed as probable, but will likely be the Packers’ No. 2 running back behind Cedric Benson.

Follow Packers reporter James Carlton on Twitter: @CBSSportsNFLGB and @jimmycarlton88.