NAPA — Not long after watching the first practice of a Raiders team widely considered one of the worst in the NFL, Reggie McKenzie stood on the vacated field grinning and trying to contain his, ahem, excitement.

How can any general manager revel in uncertainty at quarterback, unaccomplished receivers, a refurbished offensive line and a brand new offensive system?

Does the heart really sing at the thought of a defense with eight or nine new starters culled from an odd lot of youngsters, NFL vagabonds and a single decorated veteran, Charles Woodson, hoping to make one final statement before retirement?

This is McKenzie’s roster, assembled with hubris, faith, hope and no small amount of duct tape. He cannot disclaim it, no matter the results, so he embraces it.

“I like being the underdog. I really do,” he says, mysterious grin materializing.

“But we have expectations here,” he adds, dropping the smile. “And I know outside the Raider walls, there are certain levels of (negative) thoughts.

“But I’m looking forward to September.”

How sweet the serenity of low expectations. McKenzie is acutely aware that NFL observers see a roster with too many pieces picked up from recycling bins around the league and conclude Oakland will lose at least 12 games.

And, honestly, there is no rational argument otherwise.

Yet Reggie is grinning, perhaps because he realizes five or six wins would exceed typical expectations, thus validating his ongoing radical makeover and, probably, granting Dennis Allen a third year as head coach.

It’s sad that the Raiders have come to this, but McKenzie is correct to assume five or six wins would be at least mildly satisfying. And he has been around the NFL nearly 30 years, long enough to know it takes a special kind of awful to lose 13 or 14 games.

“I think we … I make no predictions, but I do know we’re going to play well,” McKenzie says. “We’re going to play some good football. I know we’ll be better. I know we’ll be better. I have no doubts about that.”

If the words seem bold, perhaps even delusional, understand that McKenzie has been given the latitude and, presumably, the time to rebuild this roster. Owner Mark Davis consistently says he supports Reggie and, moreover, realizes this process could take several years. M.D. is OK with that, as long as there are tangible signs of progress.

To repeat, there must be tangible signs of progress.

After going 4-12 last year, tangible progress is defined by 5-11 — and the peace of mind that comes with having created salary-cap breathing room, which McKenzie has.

Can the Raiders get to five? They play four games against the rebuilding Chiefs and the inconsistent Chargers, and a fifth against woeful Jacksonville. Washington, with a recovering Robert Griffin III, visits in September. Tennessee comes to Oakland in November. Mark Sanchez and the Jets can lose to anybody.

Reasonable defense can keep the Raiders in games, and theirs almost has to be better. Allen expects it, and coordinator Jason Tarver almost seems assured of it, insisting there is a new culture of accountability among his charges.

“Our guys already show a propensity for enjoying playing with each other,” Tarver says. “We know it’s going to get hard in training camp, and it’s going to get hard when you play some of the good quarterbacks. But when it gets hard, we’ll be ready for it.”

Still, no one in the building has more to prove than McKenzie, who was granted broad powers when he took the job in January 2012. He chose the new quarterbacks, veteran Matt Flynn and rookie Tyler Wilson. He made the gutsy call to use the initial first-round pick of his G.M. career on a gifted cornerback with a disturbing injury history.

If D.J. Hayden is healthy and productive, Reggie gets major bonus points. If not, his first opportunity to draft a star becomes a monumental misjudgement.

McKenzie believes in what he has, mostly because he is convinced this new group is mentally tougher and more committed.

“I’m eager. I’m very eager,” he says. “I’m confident in some areas. But it’s exciting to me, because when you add so many new guys, you want to see how they mesh. You want to see how some of them develop. And we’ve even added four new coaches. I want to see how that meshes.

“So far, it’s been good. I’m excited.”

So far, there have been no games or losses. No new injuries or broken plays or mental errors. There’s not a lot of anything except low expectations, and those have never been more welcome in Oakland.

Contact Monte Poole at mpoole@bayareanewsgroup.com. Follow him at Twitter.com/1montepoole