Matt Cassel will be the starting quarterback for the Minnesota Vikings on Sunday against Pittsburgh as Christian Ponder recovers from a rib injury.

Ponder was hurt early in last Sunday's game against Cleveland, but managed to finish the contest. He was limited in practice this week, giving Cassel the majority of reps with the first-team offense.

"I feel like I'm ready to go, I've had a good week of practice," said Cassel. "Now it's about going out there and executing on Sunday."

Ponder was hoping to play Sunday with the aid of rib protection, saying earlier this week that his biggest concern was contact, but coach Leslie Frazier decided the risk of further injury was too great.

"Christian had a fractured rib and we felt it was just too risky to put him out there and take a hit," said Frazier on Friday. "He's a tough, tough guy, but it probably wouldn't be wise to put him in that situation. We have complete confidence that Matt will do a good job."

Cassel joined the Vikings in March after spending the past four years in Kansas City. A poor 2012 season sealed his fate with the Chiefs, who acquired Alex Smith in a trade with San Francisco.

Ponder, meanwhile, has struggled somewhat as the Vikings have opened with three straight losses. He has completed 59 percent of his passes for 691 yards with two touchdowns and five interceptions in three games.

"He's a competitive guy, he's played through some injuries during his time here in Minnesota," added Frazier. "He wanted to play. It was tough for him to get the news that we were going to start Matt. The fact that we have a bye coming up gives him a little more time to heal."

Should Cassel play well Sunday, the week off could give Frazier time to consider a permanent switch, although it's something he doesn't expect to happen.

"I don't foresee a quarterback controversy, but we want Matt to have the best game of his NFL career on Sunday," Frazier continued.

The 31-year-old Cassel first joined the Chiefs in 2009 after leading the Patriots to 11 wins while Tom Brady missed the 2008 season with a knee injury. After the Chiefs struggled in Cassel's first year, he helped the club to a surprise AFC West title in 2010, throwing for 3,116 yards with 27 touchdowns and just seven interceptions.

However, the USC product played just 18 games over the previous two seasons because of injuries and ineffectiveness. He suffered a concussion last October and played just nine games in 2012, throwing for 1,796 yards with six touchdowns and 12 interceptions.