Adrian Peterson missed nearly the entire 2014 season and elected not to play at all in the preseason, making the rust appear evident in Week 1.
"It felt good to get out there, play some football, take some hits," Peterson said. "But [it was] definitely embarrassing to perform the way we did."
Peterson, 30, didn't touch the ball until the second drive of the game, as the Vikings threw on their first three plays.
Asked whether he thought he'd get the ball on the first series, Peterson said, "I don't know. I assumed at least one carry.
"I don't question Coach Turner," he said, referring to offensive coordinator Norv Turner. "He's been doing it for a long time. I trust him. I got the ball a couple of times in the second series. It is what it is."
Peterson admitted after the game he felt "a little hesitant a couple of times coming out of the shotgun.
"You really just need to be more patient, allow the pulling guard to get on his block and hit it up in there. Those are the ones I felt like I was kind of hesitant on. I really wanted to hit like I was coming out of the I formation."