FLORHAM PARK, N.J. -- An MRI exam of Mekhi Becton's right knee revealed a more serious injury than initially anticipated, a source told ESPN on Monday night, raising fear that the New York Jets' starting right tackle could be sidelined indefinitely.

The 2020 first-round draft pick injured the same knee that required season-ending surgery in September, but this was described as a "different" injury, the source said. Becton will have additional tests on Tuesday to determine a diagnosis, but the Jets' concern level was elevated after receiving the MRI results. One source said the assumption is that Becton, 23, will miss significant time.

A source told ESPN's Jeremy Fowler that Becton sustained an injury to his patella (kneecap).

Becton appeared to hurt the knee in an early O-line drill Monday morning. He limped around but stayed in practice. A few minutes later, on the second play of an 11-on-11 period, Becton fell backward after being jolted by defensive end John Franklin-Myers. Becton's right foot seemed to get caught in the grass, perhaps causing his knee to bend awkwardly.

Becton removed his shoulder pads and limped immediately to the locker room with members of the training staff.

He began wearing a knee brace on Friday, an indication that he might have started to feel discomfort. One source said it was nothing more than typical training camp soreness.

After Monday's practice, coach Robert Saleh was cautiously optimistic, saying preliminary tests indicated no serious injury. Based on what he was told by doctors, he said the knee was "stable" and the MRI was precautionary.

"As of now, it doesn't seem like a big deal, but -- knock on wood -- hopefully that stays the case," Saleh said.

For Becton, who has a history of injuries and conditioning issues, any time lost could be potentially significant. Late Monday, the Jets signed well-traveled veteran Caleb Benenoch (23 career starts) to a one-year contract. They remain interested in free agent tackle Duane Brown, a five-time Pro Bowl selection who visited with them over the weekend.

Becton injured his right knee in the 2021 season opener and never played again, even though the team initially called it a four- to six-week return from surgery.

With Becton's latest injury -- and with backup swing tackle Conor McDermott sidelined one to two weeks with a sprained ankle -- there is a greater sense of urgency to add an experienced tackle. Starting left tackle George Fant also is returning from knee surgery, although he is healthy and practicing.

Saleh downplayed the team's interest in Brown, saying the Jets have "so much great talent" at tackle and that Brown would be a luxury.

"It doesn't create panic in my mind at all," Saleh said. "A guy like Duane is a bonus."

But that was before the MRI result.

Becton has started only 14 out of 33 games in two seasons, including six games he didn't finish because of various injuries. His weight became a major storyline last season, when he reached about 400 pounds as he recovered from surgery.

He was overweight at the June minicamp, which frustrated the organization, but he trained at the facility before camp and reported in acceptable shape. Saleh praised Becton for powering through the first nine practices as he worked his way back into football shape.

Now it could be a challenge if he has to miss time.

"We'll see if he does take time off," Saleh said. "Obviously, you're concerned for everyone. ... You just don't want to get into a deficit of conditioning. He's a big man. He's been working his tail off, and he's done everything he's been asked to do. Hopefully, he checks out good like we think he's going to and he can continue on this track. I think he's going to be fine."

By nightfall, that optimism had faded.