From Jets Confidential, here is an excerpt that lists Jonathan Carter as a possible replacement and three guys who we could draft late.
So what will the Jets do to replace Morton, who was arguably the NFL's best kick returner last year? Right now, the leading candidate for the job is speedy wideout Jon Carter, who they claimed off waivers last year from the Giants. Also expect them to draft a returner. Players like Stanford's Ryan Wells, Mississippi's Jason Armstead or USC's Darrell Rideaux are possibilities. Rideaux is considered by many to be the best returner in the draft.