David Clowney had four receptions for 72 yards against the Dolphins.
Cotchery didn't practice for the second day in a row because of a hamstring problem.
"It doesn’t look very good," Ryan said after Thursday's practice in Florham Park, N.J.
Cotchery, the club's No. 1 receiver before Braylon Edwards came aboard from Cleveland, missed practice time last week and was listed as questionable for Monday night's game against the Miami Dolphins. But Cotchery played and caught one pass for 4 yards.
"You never know," Ryan said. "Some of these guys really know their body and the fact that he finished the game, he had almost 30 reps, I think is a positive thing. He's just sore."
Cotchery's injury increases the importance of third receiver David Clowney and tight end Dustin Keller. Clowney had four receptions for 72 yards against the Dolphins, but Keller was thrown to only once and didn't have a catch.
"He's certainly a threat," Ryan said of Keller, "but I think some games there are going to be more opportunities for David Clowney, for Braylon, for whoever, and then sometimes it swings back around for Dustin Keller or your running backs.
"You don't want to force the issue, though. That's when you get into trouble. If for whatever reason they're playing a certain type of coverage, where they're doubling Dustin, then you've got to look at different spots."
Keller's season has been disappointing so far. He has a dozen receptions for 171 yards and one touchdown.
"He's got to keep working to get open," Ryan said. "He's a great athlete. To me, he's one of the premier receiving tight ends in the game. Hopefully we can get him on track and get him some passes. That will be another great weapon."