"I've done a lot of thinking and come to the conclusion I'm going to suspend him for this game," Reid said during his Wednesday press conference. "He'll be back the following week."
Peters received an unsportsmanlike conduct penalty following a defensive holding call against teammate Steven Nelson during an unsuccessful two-point conversion try by the Jets. Peters picked up the official's flag and threw it into the stands, then walked off the field to the locker room.
Reid said Peters believed officials disqualified him from the game. He later returned to the sideline, but did not re-enter the game.
The head coach declined to offer details of his discussion with Peters or the exacts reasons for the suspension, other than he based his decision off what happened during Sunday's game.
"I'm going to leave all that stuff with Marcus and I," Reid said. "I'm not going to get into the details. That's not the way I roll with these things. I deal with the player man-to-man and we talk about it and discuss it and inevitably he'll come back and we'll move on from there."
Peters did not appear in the team's locker room following the game. Reid said the suspension meant Peters would not practice this week and will return to the team Monday. The cornerback's only public comment came from via Twitter Tuesday morning: "Lol."
Quarterback Alex Smith said he officially learned of the suspension Wednesday morning.
"Nobody likes to lose and when you have a lost a few in a row, sometimes funny things happen," Smith said. "It gets to people and it's a tough situation. Coach made the decision though and we're going to go with it. Stakes are too big right now with what we've got in front of us, the opportunity in front of us."
The episode on Sunday served as the latest breakdown in discipline for the All-Pro cornerback. Peters received a one-game suspension during his junior year at Washington for a sideline tantrum. The school dismissed Peters later in the season for disciplinary issues.
Last season Peters twice punted a ball into the stands during a game in celebration, earning just a single delay-of-game penalty but a stern reprimand from Reid. Sunday's penalty marked his third unsportsmanlike conduct foul of the season and fourth of his career. Peters also received an unnecessary roughness penalty against Oakland in Week 7, which sparked an incident leading to the disqualification of Raiders running back Marshawn Lynch. The two teams meet again this week, with Peters on the sideline.
Reid said he discussed the suspension with the team's leadership after he made the decision.
"I like Marcus Peters so that's a difficult thing to do," Reid said. "Anytime you have to do one of these type of things, that's not the best part of the job, no. But again, I've always told you, I'm going to do what I feel is best for this organization for that time and I try to set back and evaluate it, and that's what I did with this and this is the conclusion I came down with."
Smith said he believe the team's leadership stands prepared to move on this week without Peters.
"I can't speak for everybody in here, but certainly I know a lot of the leaders on this team I think are ready to go," Smith said. "I think they understand it. It's not easy, this is a hard situation, a hard decision, coach made it and we're going. To go back and forth on all this stuff at this point is pointless a little bit. Let's go."