Matt Cassel visualizes himself taking snaps during games.

The Journal / Mary Murphy

PHOENIX — Matt Cassel knows that most Patriot fans don’t want to see him play.

At least not in a Patriots uniform and especially not this weekend in Super Bowl XLII against the Giants.

Because if that happens, it probably means that Tom Brady, arguably the greatest quarterback the NFL has ever seen, has been injured.

Even his teammates would rather see him remain on the bench.

“I hope I don’t see him this weekend,” Brady said, “unless he is kneeling down the ball.” In other words, doing mop-up duty because the Pats have a big lead in the final seconds of the game.

But that doesn’t mean Cassel isn’t a good quarterback.

Both receivers Jabar Gaffney and Kelley Washington have said that Cassel is a capable quarterback.

Cassel has been playing second-fiddle to quarterbacks ever since he left Chatsworth (Calif.) High School where he was named an All-American and an All-Star by numerous media outlets.

That wasn’t the way he planned it when he left high school. But he was forced to serve as a backup to Heisman Trophy winning quarterbacks Carson Palmer and Matt Leinart at USC.

After getting injured, Palmer red-shirted a season and stayed an extra year, which forced Cassel to red-shirt his freshman season. When Palmer left, Leinart beat Cassel out for the starting job. Even though Cassel saw limited action in college, the Patriots picked him in the seventh round (230th overall) of the 2005 draft.

Cassel has played in 14 games for the Patriots since then. He has completed 22-of-39 passes (56.4-completion percentage) 253 yards and two touchdowns with two interceptions for a 71.8 quarterback rating.

He prepares for each game in an unusual manner — by visualizing himself at quarterback during every play of the game.

“During the course of the game, I try to keep my helmet on because what happens is, the coach relays the play to the quarterback and we hear it in our helmet,” Cassel said. “From there what I usually do is I say the play out loud as if I was in the huddle.

“Then I break the huddle and I go to the line as if I was on the line of scrimmage with the guys and watch the defense as it operates, go through my checks, try to go through my reads — where I would go with the ball — and just try to play the game through visualization mentally on the sidelines as if I were in there.

“It’s just something that I feel is necessary for me to do — to be as prepared as possible if my time were to come up because if you are standing on the sideline, you’ve got your hat on and you’re not doing anything, your just chewing on seeds and then all of a sudden something happens and you haven’t been watching and paying attention to the details of the game throughout the course of the game. I think that sets you back a little bit because you are not used to what’s going on out there and seeing the different plays, so I just try to be as prepared as possible and that’s just something that I’ve done for a long time.”

Cassel has had only seven pass attempts this season (4-for-7, 38 yards, 1 interception) but he said that he has made sure that he knows the Patriots opponents’ defense inside and out every week.

In fact, he said, all of the Patriot quarterbacks take a written test at some point during the week on their plays and their opponents’ defense.

“It’s just something to keep you sharp and it reminds you if throughout the course of the game, if something comes up, you go, ‘OK, I got that. We rehearsed it. I’ve studied it on a test.’ It’s just little things that keep you sharp,” Cassel said.

If Brady goes down, Cassel’s teammates have confidence in him that he can get the job done.

“He’s been doing a great job at what he does,” Patriots linebacker Junior Seau said of Cassel. “He’s hanging around and waiting for his opportunity and that’s a lot of perseverance. He will get his chance, but he’s just playing behind the best quarterback to ever play. There are a lot of things he can do to his advantage later on down the road. It’s going to be up to him to keep working and his opportunity will come.”

roblee@projo.com