PITTSBURGH -- Pittsburgh Steelers running back Le'Veon Bell has a mid-foot sprain but not a tear associated with a more serious Lisfranc injury, coach Mike Tomlin said Thursday, providing a glimmer of good news in regard to the highly touted rookie.

A second opinion on the right foot Bell injured last Monday night confirmed that the 6-foot-1, 244-pounder does not need surgery. It also provided hope that Bell will only miss a small portion of the regular season, though Tomlin would not put a timetable on when the Steelers expect the former Michigan State star to return.

Rookie Le'Veon Bell was expected to be a key part of the Steelers' running game this year. AP Photo/Keith Srakocic

"We are optimistic and encouraged how (the situation) has developed in the last 48 to 72 hours," Tomlin said Thursday at a news conference.

Bell has already been ruled out for Saturday's preseason game against visiting Kansas City. A beat-up Steelers backfield, however, could be bolstered by the return of Isaac Redman, who has shared the top spot on the depth chart with Bell and LaRod Stephens-Howling.

Redman (stinger) and Stephens-Howling (knee) did not play last Monday night, but Tomlin said the Steelers are "leaving the door open" for each to suit up against the Chiefs.

Bell is in a walking boot and using crutches, but he said he is able to put pressure on his right foot -- something he couldn't do last Monday night after he was injured in a 24-13 loss at Washington. Bell also said the swelling in his right foot has gone down considerably.

"I feel like if my foot even gets close for me being able to play on it, I'm going to try to play on it," Bell said. "But I know it's a long season and I want to make sure everything is comfortable so I can go out there and play how I want to play.

"I don't want to go out there and play injured and then have the injury come back and get worse."

Bell, who rushed for nine yards on four carries against Washington, said he got hurt when a player fell on his leg after he had planted his foot.

"I'm going to fight through it and get on the field as quickly as possible," he said.

Staying on the field has been a problem thus far for Bell, which is surprising considering durability was one of his trademarks when the Steelers took him in the second round of the 2013 NFL draft.

Bell, the second running back taken the 2013 draft, shined during training but was hampered by a left knee injury that caused him to miss a handful of practices as well as the Steelers' first preseason game.

His mid-foot sprain has only added to the frustration for Bell and the Steelers, but Tomlin dismissed a question about whether there are long-term ramifications from the injuries that have hampered the young running back.

"I'm not concerned at all," Tomlin said. "You play football, you get hurt."

Safety Ryan Clark said Bell has proven to the Steelers veterans that he is willing to try play through injuries. Bell, Clark added, needs to get fully healthy before he returns to the field.

Bell found one positive from his latest setback.

"Me hurting my foot really lets my knee get back to 100 percent," Bell said. "So I guess you could say the foot's a blessing in disguise."