The Jets' outside linebacker will have surgery Monday in North Carolina to repair his broken right foot, and will miss New York's season opener against Baltimore on Sept. 13.
Pace could miss up to six weeks, according to the Daily News, citing a source with knowledge of the situation.
"Hopefully, it'll be a somewhat speedy recovery," Pace said Sunday. "I probably definitely will miss the first game, that's safe to say, but beyond that, I don't really have an idea."
The Jets' top pass rusher had to sit out the first four games of last season after being suspended by the league for violating its policy on performance-enhancing substances. He still led New York's top-ranked defense with a career-high eight sacks.
"I'm still upbeat, I really am," Pace said. "Stuff happens in football. I'll say this: It's better to get injured playing rather than have to sit out four games because of a silly mistake as far as a supplement. It happens and I'm going to stay upbeat and cheer the guys on."
The procedure will be performed in Charlotte, N.C., by foot and ankle specialist Dr. Robert Anderson, who has treated several NFL players including Plaxico Burress, Brady Quinn, Felix Jones, Leonard Little, Ahmad Bradshaw and Aaron Ross.
"We'll know more about the extent of the injury, obviously, after the surgery," said coach Rex Ryan, declining to put a timetable on Pace's return.
Pace was injured in the third quarter -- during the starters' last series -- of New York's 16-11 preseason loss to the Washington Redskins on Friday night. He said Redskins tackle Stephon Heyer tried to cut block him.
"I tried to block him away," Pace said, "but I guess his helmet hit the side of my foot."
X-rays in the locker room revealed a fracture, and Pace refused to call it a dirty play.
"Nah, that's football," he said. "It happens. I guess I should've gotten my foot out of the way a little quicker."
Jason Taylor, the NFL's active career sacks leader, and Vernon Gholston are expected to handle the bulk of plays at Pace's spot in his absence. But Ryan also acknowledged having spoken to former Baltimore Ravens linebacker Adalius Thomas, a favorite of his when he was an assistant there.
"I would say it would be a possibility," Ryan said. "I'm not going to rule that out."
NFL Network insider Michael Lombardi reported on Sunday that the Jets would not be interested in bringing Thomas aboard until after Week 1. If the club signs Thomas before the start of the regular season, it would guarantee the veteran a full year's salary.
Ryan said there were no plans to bring Thomas in for a physical as of Sunday afternoon, while hinting at the economics of the situation.
"There's still some other things involved, other factors involved," Ryan said. "Sometimes what really makes sense might not make sense to the organization, so we'll see."
The team needs to evaluate where Thomas would fit on the roster, and who would have to be let go before it signed him. Thomas, who was mostly disappointing the last three seasons with New England, was a two-time Pro Bowl selection with the Ravens.
"I don't want to bring A.D. up here not to have a roster spot for him if he plays the way we expect him to play," Ryan said. "Right now, I can't say specifically that he would be on our team, so I don't want to bring him in until I know that if he plays to expectations that there would be room for him. That's something we're looking into."
Ryan is also unfazed by the prospect of not having his top pass rusher and shutdown cornerback in Darrelle Revis, whose holdout reached 29 days, in Week 1.
"We've got enough depth here, enough good football players that offenses need to be worried about our defense," Ryan said. "We're definitely not worried about it."
Notes: Ryan said the established starters on offense and defense will not play at all in the Jets' preseason finale at Philadelphia on Thursday so he can "keep them fresh." ... Quarterback Mark Sanchez fell hard on his right shoulder against Washington, but Ryan said he was fine and had "no limitations whatsoever" Sunday.
The Associated Press contributed to this report.