Head coach Bruce Arians agrees.
In his meeting with the media on Monday, Arians didn't beat around the bush with Peterson's performance. "I thought it was probably his poorest game since I've been here," Arians said.
Peterson was flagged three times during the game, including a blatant grab of Victor Cruz in the end zone that would lead to a one-yard touchdown pass soon after. He also allowed a touchdown pass to Reuben Randle.
Peterson was visibly bothered by the penalties. He bumped an official trying to make his case and was lucky he wasn't ejected. The pass interference penalty was the result of his frustration.
There is an increased emphasis by officials to keep the coverage on receivers clean, which has resulted in more penalties called on defenders, as they must learn to keep their hands off. While many fans would criticize the number of penalties, Arians said the officials in the game on Sunday "called a heck of a game."
But despite the touchdown and the penalties, Peterson's numbers don't look awful.
According to Pro Football Focus, Peterson was targeted six times. He allowed four catches for 33 yards, including the touchdown, and was penalized thrice. The penalties get the attention, but the actual numbers aren't bad.
Through two games, he has allowed six catches for 56 yards. He is credited with having given up two touchdowns.
Penalties aside, if this was Peterson's worst game in just over a season, that's really quite something.