Revis did practice on a limited basis Wednesday, but his status for Sunday's game against the Miami Dolphins remains uncertain.
Quarterback Mark Sanchez, who took a blow to the head in the Jets' 27-10 loss to the Pittsburgh Steelers last Sunday, is experiencing lower-back tightness, Ryan said. Sanchez, however, took his normal reps in practice Wednesday.
"I felt good for practice ... It's nothing that will hold me out," he said. "It's just a little tight. Everybody's got something."
Added Ryan: "I just found out about it today. I don't think it's that serious."
Nevertheless, having his two most important players on the injury report has to be of some concern for Ryan. Without Revis, the Jets' pass defense was no match for the Steelers' Ben Roethlisberger, who passed for 275 yards and two touchdowns.
Revis' status hasn't changed since Friday, when he returned to the practice field for light, noncontact work. A short time later, Ryan ruled him out for the Pittsburgh game. Revis agreed with the decision, admitting he wasn't 100 percent.
On Monday, he said he felt "a lot better" but acknowledged the decision is out of his hands. Based on NFL protocol, a concussed player must be cleared by the team doctor and an independent neurologist before returning to contact.
"We'll see how that progresses," Ryan said.
There was some concern that Sanchez, the victim of a helmet-to-helmet hit by linebacker Lawrence Timmons, had suffered a possible head injury in Pittsburgh. After the game, Sanchez said he was fine, and Ryan echoed that sentiment Monday.
Sanchez doesn't have a history of lower-back issues, but he played the latter part of last season with a pinched nerve in his neck, causing occasional discomfort in his throwing shoulder.
He's coming off one of the worst games of his career. Sanchez completed only 10-of-27 passes for 138 yards and a touchdown. After the hit by Timmons, he went only 6 for 22, missing an open Santonio Holmes in the end zone for a would-be touchdown.
Tight end Dustin Keller, who missed the Pittsburgh game with a pulled hamstring, didn't practice. But he said his condition has improved and, barring a setback, he expects to play Sunday.