EDEN PRAIRIE, Minn. (AP) - Mike Zimmer and the rest of the new Minnesota Vikings coaching staff have spent countless hours since taking over getting to know their new players, working with them on the practice field to identify strengths and weaknesses, and implementing new systems on offense and defense aimed at turning around a team that finished 5-10-1 last season.

The results to this point have been a quietly impressive preseason in which the new-look team went 4-0 and started to gain the confidence needed to coalesce around a first-time head coach.

Zimmer knows that all that work, while valuable, pales in comparison to what happens in the regular season, when every decision is scrutinized and every misstep is magnified. So in that respect, Zimmer's first true test comes on Sunday when the Vikings open the season at St. Louis.

''The only thing I have to judge, I know the score is up there, but in the preseason it's more about are we doing things right,'' Zimmer said Wednesday. ''Are we playing real hard? Are we playing smart? I think to this point we've done that. Every week is different in the NFL, every one of the 16 weeks. Just hopefully you continue to do those things. If you do those things you have a chance to win.''

Zimmer's plain-spoken demeanor and plain-to-see intensity have been an early hit with his players. They have rallied around the way their head coach confidently carries himself in practices, in the film room and on game day. Zimmer admitted earlier this week to being nervous for the preseason opener because it was the first time the long-time defensive coordinator was in charge of everything.

As the exhibition season wore on, he grew more comfortable as the head coach, but still anticipates there to be a learning curve in his first season on the job.

''I'm going to try to do the best job I can in each of the situations and I'm sure that I'll make some mistakes but hopefully I'll learn from them,'' Zimmer said. ''I made plenty of mistakes as a defensive coordinator, too. The more you're in those situations, the more you learn.''

He said he plans to apply the same pragmatism to veteran quarterback Matt Cassel, who earned the starting job in training camp over first-round draft pick Teddy Bridgewater. Zimmer likes Cassel's experience and leadership and said he doesn't ''want to have a quick hook.''

''If we throw an interception on the first play, I'm not going to yank him,'' Zimmer said. ''I have to go on the OTAs and everything we've seen from there. I know the fans are excited about Teddy. I'm excited about Teddy. But we have to do what's best for the football team at this point in time and what's best for the future.''

Cassel knows what it's like to be caught in a revolving door. The Vikings started three different quarterbacks last season and Cassel only decided to return after being assured that things would be different under the new regime. He's been atop the depth chart all summer long and wants to keep it that way.

''I've worked as hard as I've ever worked and I'm not going to look over my shoulder,'' Cassel said. ''You can't think about if I make a mistake, what's going to happen next. You've got to go out, play the game to the best of your ability. I think Teddy does have a tremendous future, but hopefully as long as I'm here he's not playing.''

As good as the first impression has been for Zimmer, the environment changes entirely starting Sunday.

''Anytime the regular season starts, that's why we all get paid, the players and coaches,'' safety Harrison Smith said. ''So everything is kind of cranked up a little bit. And I'm sure there's going to be some creases here and there we haven't seen yet in the preseason just because everybody's amped up. But I'm confident in everybody adapting and performing well.''

NOTES: Zimmer named Jasper Brinkley the starter at MLB and Robert Blanton the starter at SS for the opener. He called those decisions ''week-to-week'' and left the door open for them to be reevaluated as the season goes on. ... The Vikings cut OT Mike Remmers from the practice squad and signed former Dallas Cowboys S Ahmad Dixon to the practice squad. Dixon was a seventh-round pick in the draft.