NEW ORLEANS -- Saints head coach Sean Payton said he thinks that quarterback Jameis Winston suffered a "significant" knee injury before being carted off the field in the second quarter of Sunday's 36-27 victory over his former team, the Tampa Bay Buccaneers.

"I cried when I saw him coming in," acknowledged Payton, who said he was waiting to speak with doctors before giving a more detailed diagnosis. "It's hard."

Winston, true to form, was still dancing while on crutches in the Saints' postgame locker room celebration, according to teammate C.J. Gardner-Johnson's Instagram feed. Winston also tweeted a "WHO DAT!" after the game.

Veteran backup quarterback Trevor Siemian replaced Winston and led the Saints (5-2) to an improbable win that was clinched by Bucs quarterback Tom Brady's third turnover of the game -- an interception returned for a touchdown by defensive back P.J. Williams with 1:24 remaining.

It's unclear who will start at quarterback for the Saints in Week 9 at home against the Atlanta Falcons -- or for the remainder of the season if Winston misses significant time. Taysom Hill would be a natural candidate for the role, but he has been sidelined by a concussion since Week 5, though he has been progressing in his recovery.

Winston was injured during a horse-collar tackle by Buccaneers linebacker Devin White -- who was flagged 15 yards for pulling Winston down by the shoulder area of his jersey, forcing Winston to land awkwardly. Winston's left leg got pinned behind him as he hit the turf. Trainers and medical staff examined him on the field before helping him limp slowly to the sideline and into the medical tent. He was later assisted onto a cart and driven back to the locker room.

Winston completed 6 of 10 passes for 56 yards and a touchdown and scrambled four times for 40 yards before leaving the game with the score tied 7-7. For the season, Winston is 95-of-151 passing (59%) for 1,170 yards with 14 TDs and three interceptions.

"First I want to say how gutted I am for Jameis. This win was for him," said Siemian, who completed 16 of 29 passes for 159 yards and a touchdown. "I just feel for the guy, I love him so much. Just being around him, you can't help it, he's got this infectious personality. And you're just frickin' gutted when you see anybody hurt. But watching him get hurt was tough."

Siemian is 13-12 as a starter in his career -- but hasn't won a game since 2017 with the Denver Broncos. He estimated that he had "200ish" texts waiting for him after the game, but joked that, "Most are from my mom."

"I kind of lost the sense of how fun it is when you're out there in a huddle and in the middle of a drive and you score," Siemian said. "There's a joy to this game that you can't get chasing anything else, and that was kind of fun to do that."

Williams, who caught the clinching interception, was actually a teammate of Winston at Florida State and was one of many Saints' players who voiced their support for Winston after the game. Payton said he gave Winston a game ball. Several teammates hugged Winston on his way off the field, including injured receiver Michael Thomas, who was watching the game on the sideline in street clothes.

White also said he went up and tapped his former teammate on the head, saying, "I hate that this happened to you, man. Because you're playing good ball and just praying for you."

"Because, man, Jameis is a good guy. He's a great guy. I'm gonna put an emphasis on that," White said of Winston, who played with the Buccaneers from 2015 to 2019. "All last year when they [were] playing and we [were] playing, he was texting -- I don't know if he was texting everybody, but me and him [were] close. When I came in, he kinda showed me around -- and just telling me how proud he was of me. Even when we won a Super Bowl, he was one of the first texts, like, 'Congratulations, man. I wish I could be a part of that, but y'all deserve it. You put a lot of work in, and we always talked about how special you all could be.'

"He's a great guy. You hate to see that happen. I hope it's not serious, man. I'm just praying for him. But it's a long season. [I] hope he can come back and fight with his team."

ESPN's Jenna Laine contributed to this report.