NAPA -- The Raiders and their fans would be forgiven if they took a wait-and-see approach on rookie linebacker Khalil Mack.
After all, it was only four years ago when linebacker Rolando McClain arrived with a lot of hype as the eighth pick out of Alabama, only to get cut after three seasons and classified as a massive bust.
However, everyone is all-in on Mack, convinced that he is the real deal, the kind of can't-miss prospect that the Raiders whiffed upon in the first round eight times since 2003.
"I've seen a lot of defensive rookies come in over the years, but the difference with this guy is, he's more polished," veteran offensive lineman Khalif Barnes said. "He has all the tools of an elite pass rusher in this league."
Mack joined the Raiders in May as the No. 5 pick out of Buffalo. He hasn't done anything in the three months since to make anyone question the selection.
The next test for Mack is showing what he can do in a game. He gets his first crack Friday, when the Raiders play the Minnesota Vikings in both teams' exhibition opener.
Mack said he isn't much into self promoting. He's just eager to do what he does best, play football.
"We'll be able to see Friday," Mack said, when asked if he knows what kind of player he's going to be in the NFL. "I can't tell you what kind of player I am or what kind of player I'm going to be, but I can show you."
When pressed on the issue, Mack said:
"There's a lot of talking involved in this level of play. I'm not a talker. I'm all about action. I like to go out and play football and show you what I can do instead of telling you."
For that, let's listen to left offensive tackle Donald Penn, who oftentimes is assigned to block Mack in practice.
"From what I've seen so far, he's going to be one of those guys that you talk about for a long time," Penn said.
Penn said Mack has that rare combination of speed, strength, instincts and intellect. If Penn doesn't do everything just right on a given play, he said, Mack will exploit the weakness and "make me pay for it."
Moreover, Mack always wants to know what he did wrong on a particular play, Penn said. Or he wants to know why he beat Penn.
Mack beat Penn twice in a one-on-one blocking drill Wednesday, and he still was in Penn's ear an hour after practice ended.
"He's getting better and better every day," Penn said. "He's growing well as a player. I can't wait to see him unleash it."
Second-year player Mychal Rivera and Ausberry are competing for the starting job. Rivera ascends to the top of the pecking order with Ausberry sidelined. Nick Kasa and Brian Leonhardt suddenly are competing for the primary backup spot.
Ausberry suffered a shoulder injury during training camp last season and missed the entire season.
Cornerback DJ Hayden (foot), safety Usama Young (quadriceps) and guard Lucas Nix (knee) remain on the physically unable to perform list.
Raiders at Minnesota, 5 p.m. KTVU