"For me, I'm just not playing to the best of my ability and, quite frankly, just playing stupid," the rookie told reporters Monday on a conference call. "I thought I played stupid football [Sunday]. I just have to be better. I know that, the coaches know that, everybody knows that."
Darnold's interception total ballooned to a league-high 14 with a four-pick performance in a 13-6 road loss to the Miami Dolphins. He threw an interception on three of the Jets' last four possessions, including one that was returned for a touchdown by linebacker Jerome Baker.
For the first time since he was named the starter before Week 1, Darnold expressed self-doubt.
"I just have to play smarter, play better," he said. "Yeah, I definitely feel like I forced some things. But at the same time, I feel like there were some throws [I didn't make] where I was second-guessing myself and I could've pulled the trigger.
"At some moments in the game, I just get in my own head. I just have to stay true to my progressions and make sure [I have] the confidence I normally have. Just go out there and sling it."
After a promising start to the season, Darnold -- drafted third overall -- has slipped into a three-game funk. In those games, all losses, he has seven interceptions, only two touchdown passes and a passer rating of 43.3.
The Jets have dropped to 3-6. They face the Buffalo Bills (2-7) on Sunday in a battle of two struggling offenses.
Darnold said "the frustrating part" about Sunday was he felt the rest of the offense played well. He said the offensive line "blocked their asses off," although the stats suggest otherwise. He was pressured on 41 percent of his dropbacks, according to ESPN Stats & Information. He was sacked four times.
"It was just me turning the ball over," he said. "That was really the only thing. If I don't turn the ball over, I feel like we have a good chance to win that ballgame."
Coach Todd Bowles reiterated that he has no plans to make a quarterback change.
"Not at this time, no," he said.
The Jets' backup is Josh McCown, 39, who has yet to take a snap.
"He made some bad throws he'd like to have back," Bowles said of his rookie. "It wasn't his cleanest game to date."
Bowles was careful not to criticize Darnold, but he acknowledged the former USC star "had a couple of bad reads and that kind of crept up [Sunday]."
This is a pivotal point in Darnold's development. The Jets don't want to handcuff him, but they also know they can't win if he continues to force passes into coverage.
"He knows he has to play within the system," Bowles said. "He understand when he can and can't make throws. You want him to make throws and make big throws, but you don't want him to force them."
Darnold said he came out of the game with some "bumps and bruises" but also said that he's fine. Bowles said he's not aware of a specific injury.