BEREA, Ohio (AP) -- Montario Hardesty can't stop his unlucky run of injuries.
The Browns' running back will undergo arthroscopic knee surgery Thursday, the latest medical setback for Hardesty, who dislocated his right thumb on Monday after missing most of training camp with a hamstring injury.
Cleveland coach Rob Chudzinski said Hardesty has been bothered by ''nagging'' soreness in his knee, and that the surgery is not related to the hamstring injury that forced him to miss the majority of workouts this summer. Hardesty had only returned to practice on Monday when he injured his thumb while jumping to catch a direct snap from center.
Chudzinski does not know how long Hardesty, who has undergone prior surgeries to repair torn ligaments in both knees, will be sidelined.
''We'll have to see after he gets that (scope),'' Chudzinski said. ''It's just to clean it up.''
Typically, the recovery time on such surgeries is least one month. Chudzinski said his message to Hardesty is to stay strong.
''You have to keep coming back and keep fighting,'' he said. ''I think that is the theme we have been talking about a lot. It applies everywhere in this game. And he'll make it back.''
Chudzinski did not know which knee Hardesty was going to have scoped. Hardesty was limited in practice Tuesday, when he had a protective wrap over his thumb. He left without speaking to reporters.
The engaging 26-year-old has had injury issues throughout his NFL career, and before he turned pro. Hardesty tore his left anterior cruciate ligament in the final exhibition game in 2010 and missed his entire rookie season. Hardesty also had knee problems in college at Tennessee, and had his right ACL repaired when he was a freshman with the Volunteers.
He's battled back every time, and now Hardesty will have to do it again.
''That injury bug is something you can't control,'' said linebacker D'Qwell Jackson, who had had to overcome two major chest injuries. ''He's just got to stay positive. Once he has his surgery, it's just one day at a time, just look at how you can make the situation better. It starts with the attitude, attitude is everything. It's going to help the healing process and it's going to help him mentally get through it.
''I would tell him is to keep good people around him just so he stays motivated and stays with a positive outlook.''
Hardesty was drafted in the second round by Cleveland in 2010. He rushed for 271 yards as Trent Richardson's backup last season, but his roster spot was believed to be in jeopardy because of the arrival of Dion Lewis, who recently passed him on the depth chart.
Chudzinski said the Browns will have to wait to see how long Hardesty will be out before any roster decisions can be finalized.
''We'll just have to see when he gets back and then balance that with the other guys and how they are doing and how they've done in the next couple weeks,'' he said.
With Chris Ogbonnaya and Brandon Jackson, the Browns have enough depth at running back to help ease the sting of losing Hardesty.
''It's really nice having Dion in there because he's done a great job during the entire training camp,'' Pro Bowl left tackle Joe Thomas said. ''He did a great job in the first preseason game, and obviously with him and Trent and Obi, a nice little depth chart there. They'll be able to pick up the slack nicely.''
NOTES: Thomas said RB Trent Richardson playing in the preseason should help the Browns' line develop some chemistry with the second-year star. Richardson sat out all four exhibitions a year ago and never caught up. ''You can't just plug somebody in there and just expect him to know where the reads are and the cuts and how we're blocking every play,'' Thomas said. ''So having live reps with him back there is going to be tremendously helpful.'' ... Starting S T.J. Ward will be kept out of Thursday's exhibition game against Detroit as a precaution as he recovers from a nagging hamstring. ''Nothing wrong,'' Chudzinski said. ''Just want to be smart about it and get him ready for the season.'' ... CB Chris Owens practiced with the starters on Wednesday and will play against the Lions after missing last week's preseason opener against St. Louis with a strained foot arch. Owens is competing with Buster Skrine for the starting spot opposite Joe Haden. ... WRs Jordan Norwood (hamstring) and David Nelson (knee) and P T.J. Conley (groin) did not practice as the Browns did their final tuneup for the Lions. ... Undrafted rookie OL Chris Faulk had arthroscopic knee surgery Monday, Chudzinski said.