He had to wait a little longer than he expected to make his preseason debut on Saturday night, in relief of veteran A.J. Feeley.
Bradford was warming up midway through the first quarter and ready to enter the game during the team's second series if St. Louis got a first down, which didn't happen.
Then Danny Amendola returned a punt 93 yards for a touchdown with 1:29 remaining in the first quarter to give the Rams a 7-0 lead.
The rookie from the University of Oklahoma was ready to go in a few minutes after the St. Louis defense stopped the Vikings on third down, but Amendola fumbled his next punt return.
"The second time we had the ball coach told me if we got a first down I was going in there," Bradford said. "Then we went three and out. Then I'm over there waiting and we ran the kick back and then had the fumble. I was very anxious to get in the game but once I got in there it felt great."
Bradford finally entered the game with 12:09 remaining in the second quarter when the Rams took over on first down at their own 22-yard line. The 2008 Heisman Trophy winner led St. Louis on a 10-play drive that covered 42 yards but stalled when a fourth-down run came up short.
His first pass was dropped by tight end Darcy Johnson, but Bradford completed his second pass to Laurent Robinson for 18 yards. On his first series, Bradford completed four of six pass attempts for 39 yards.
"I'll tell you that first series I believe it was a 10-play drive, I think we were on about 43 yards or so, the disappointing thing was at the end it was third-and-one, tried to convert a fourth-and-one, didn't do it," Rams coach Steve Spagnuolo said. "It would have been nice to see what would have happened if we had kept that drive going. After that it got a little bit rough for him, we had some issues that we have to get ironed out up front and some of the things we did made it a little bit tough on Sam, but we'll watch the film and we'll get it ironed out."
The Vikings took a 14-0 lead on their next possession when Rosenfels found tight end Garrett Mills running past a linebacker for a 65-yard touchdown pass with 6:45 remaining in the second quarter.
The rest of the first half didn't go so well for Bradford. He had three incompletions, including a tipped ball, in his second series. Then he had a pass knocked down and was sacked on consecutive plays in his third series.
In those three series, Bradford completed four of his 10 passes for 39 yards.
Minnesota led 14-7 at halftime. The Vikings had 220 yards of offense, including 207 pass yards. The Rams had 57 yards in the first half, with 49 passing yards.
Grant had four tackles and two passes defended. Selvie, the seventh-round draft pick out of South Florida, had a sack and a forced fumble and his quickness of the edge forced a false start and a holding penalty.
Bradford and the first-team offensive line played the first series of the second half.
The rookie quarterback completed his first two passes — 9-yard completions to Amendola and running back Chris Ogbonnaya — but his third pass turned into a fumble out of bounds when his arm was hit while he tried to throw. He then avoided a sack by throwing a pass out of bounds and was sacked on third-and-long on his final play.
Bradford finished the game with six completions on his 13 attempts for 57 yards in his four series of work. He was sacked four times and finished with a passer rating of 58.8.
The Vikings scored again with 3:14 remaining in the third quarter when Rosenfels connected with Marko Mitchell for a 71-yard touchdown pass to make it 21-7.
The final statistics were not pretty for the Rams, who mustered just 150 total yards including 33 rushing yards. St. Louis converted just three of 14 third-down conversion attempts (21 percent) and had only eight first downs.
The Vikings racked up 414 yards of offense, including 336 passing yards. Rosenfels torched the Rams pass defense in completing 23 of 34 attempts for 310 yards and three touchdowns. Mills, the team's No. 3 tight end, caught four passes for 106 yards and a touchdown.
The Rams return to action with their second preseason game, on the road at the Cleveland Browns, at 6:30 p.m. CT next Saturday.