Nicks is still bothered by his surgically repaired foot, which he had operated on back in May. He also is suffering from pain in his knee.
"It's a combination," Coughlin said.
Coughlin said the plan right now is just to rest Nicks until he is able to get back on the field. Nicks' status beyond this week is undetermined.
A four-year veteran, Nicks had 14 catches for 237 yards and a touchdown in the Giants' first two games of the year. He has had more than 1,000 yards receiving in each of the past two seasons.
Wide receiver Ramses Barden, who had nine catches for 138 yards while filling in for Nicks against the Carolina Panthers in Week 3, suffered a concussion in last Sunday's loss to the Philadelphia Eagles. He has yet to practice this week and can't be counted upon to play against the Browns.
Domenik Hixon, who also suffered a concussion earlier this season, is expected to start in Nicks' place against the Browns. Hixon had six catches for 114 yards against the Eagles.
The Giants (2-2) are banged up at several positions heading into Sunday's game against the Browns (0-4). Five defensive starters -- cornerback Corey Webster (hand/hamstring), safeties Antrel Rolle (knee) and Kenny Phillips (knee), linebacker Michael Boley (hip) and defensive tackle Rocky Bernard (quadriceps) -- missed practice Thursday.
Both Webster and Rolle said after practice that they plan to play against the Browns.