Matt Cassel threw two interceptions and lost two fumbles in Sunday's loss.

Journal photo / Mary Murphy

FOXBORO -- Nobody expected Matt Cassel to follow up two of the best passing days in Patriots history with a third straight 400-yard game, especially against a fierce Pittsburgh defense.

But getting to 200, at least, would have been nice.

Cassel’s season-long roller coaster ride continued against the Steelers on Sunday, as the former backup threw two interceptions and lost two fumbles, often looking overwhelmed by the league’s best defense.

Last week Cassel threw for 415 yards and three scores. This week, he threw for 169 yards, completed less than half his passes and earned a 39.4 quarterback rating.

It’s just the latest swing for Tom Brady's former backup, who has gone from being best known for not starting a game since high school to being one of only five quarterbacks with consecutive 400-yard days, to now wilting in the face of the fearsome Steeler defense.

The fans and the media have alternatively fretted and rejoiced with every performance – after Cassel’s excellent day in Miami, the talk radio stations buzzed all week with questions about whether the Patriots should put the franchise tag on Cassel next year, and find a way to keep him in case Brady doesn't come back as the same player following knee surgery.

This week the chatter figures to be different. Cassel doesn’t care.

"It's not about Matt Cassel, it's about 11 guys on offense trying to get better, and a team trying to get better. This isn’t about one guy's performance, Matt Cassel, and his stock rising or dropping. I could care less about that. I care about winning ball games, and tonight we lost, so obviously I'm upset about that," Cassel said after the game.

Cassel said he doesn’t read anything written about him, and the key to bouncing back from a performance like this is to remain on an even keel.

"Emotionally, you've just got to say this was a loss, the last one was a win, you go back to the drawing board and focus on what you need to do to get better," he said.

Cassel's two interceptions came in the second half. On one, he overthrew tight end Ben Watson, and safety Troy Polamalu picked off the tip. On the second throw, linebacker Lawrence Timmons stepped in front of a ball intended for Kevin Faulk. Cassel was also sacked five times by the Pittsburgh defense.

Even in the situations where Cassel has thrived all year, he had trouble Sunday. Cassel came into the game with the highest quarterback rating in the league on third down. The Patriots finished the game 1 for 13 on third downs, and the one success came with 10 seconds remaining.

A relentless rain seemed to affect every facet of the game, and several of Cassel’s well-thrown balls were dropped by his receivers, including two by Randy Moss.

"I missed some throws out there, maybe we missed some catches out there; that’s part of the game," he said.

Cassel refused to blame the weather or the dropped passes – and perhaps with good reason. The same weather that may have caused his receivers to drop balls also plagued the Steelers, and Steelers defenders dropped at least three Cassel passes that could have been interceptions.

"The weather's the weather. We need to do our jobs out there. They have to deal with it too," Cassel said.

Cassel was strip-sacked twice by linebacker James Harrison, both on outside rushes where Harrison beat tackle Matt Light. Cassel was blindsided on both hits, but he said that his ball security needs be more effective.

"As a quarterback, you've got to go out and take care of the ball; that's your top priority. You had the strip sacks, and you had the two interceptions, and that's really what made the difference," Cassel said.

Cassel's counterpart on the Steelers, Ben Roethlisberger, has dealt with seesawing expectations himself, from his fall on draft day to his phenomenal rookie season to his recent struggles. He said that Cassel performed well, considering the circumstances.

"I don’t think he had a bad game. Our defense is very good. They’re ranked number one for a reason. The weather wasn't easy, so I don't think any of this should go on Matt's shoulders," Roethlisberger said.

Perhaps some day Cassel will be the veteran making those comments about a first-year starter. For now, he will get back up, hit the film room and prepare for another chance to prove himself.

dbarbari@projo.com