FLORHAM PARK, N.J. -- The injuries continue to mount for the Jets.

Backup safety Eric Smith sprained a knee Wednesday in practice and won't play Sunday against the Colts. Initially, the team feared it was a season-ending injury. Chances are, Smith will miss at least a couple of games. It wasn't immediately known if it's the same knee he injured in the preseason, which caused him to miss a month.

Smith played a season-high 23 snaps last week, as the Jets used him at times with Yeremiah Bell and LaRon Landry in a three-safety package. Other times, Smith and Bell were used in tandem. Rookie Josh Bush becomes the No. 3 safety.

In other injury news, Rex Ryan confirmed that NT Kenrick Ellis (knee) will miss four to six weeks with a sprained MCL. That's what Ellis told reporters Wednesday. LB David Harris tweaked a hamstring Wednesday and will be limited in Thursday's practice.

TE Dustin Keller and WR Stephen Hill, both coming off hamstring injuries, continued to make progress and are expected to play Sunday, according to Ryan. C Nick Mangold (ankle) will miss practice for a second straight day, but he probably will be able to go" on Sunday, Ryan said.

Ryan wasn't nearly as optimistic about NT Sione Po'uha, who continues to be hampered by a lower-back injury.

Here's the pre-practice report:

Not expected to practice: Po'uha, Ellis, FB John Conner (hamstring), Mangold, WR Clyde Gates (shoulder) and Smith.

Limited practice: LB Bart Scott (toe), LB Bryan Thomas (hamstring), Hill, Keller, WR Jeremy Kerley (illness) and Harris.

Full practice: CB Aaron Berry (ribs), CB Antonio Cromartie (shoulder), LB Nick Bellore (shoulder), QB Mark Sanchez (back), LB Calvin Pace (Achilles' tendon), RG Brandon Moore (hip), LG Matt Slauson (knee), RT Austin Howard (back), TE Jeff Cumberland (ribs) and S LaRon Landry (heel).