Browns: Trent Richardson's 'soreness' in knee is worrisome

Cleveland running back Trent Richardson sat out Tuesday's practice with what coach Pat Shurmur termed a "sore knee." Richardson declined to comment when asked about the injury.

Shurmur added that the knee was being evaluated. The results of that diagnosis are unknown.

The Browns certainly hope the injury is unrelated to the slight meniscus tear that required surgery in January. Shurmur said "there's a chance" he won't play Friday in Detroit. Ford Field features turf, which might preclude Richardson from participating in the team's first preseason game.

That will allow Montario Hardesty and Brandon Jackson to take more reps as they continue to battle for the backup spot. Both have returned from injuries last year to perform well in camp. Hardesty has regained the speed and quickness that motivated the Browns to move up and take him in the second round of the 2010 draft.

Though it's far too early to speculate, the loss of Richardson would be a tremendous blow to the Browns, who have already lost weak-side LB Chris Gocong (Achilles) for the year and DT Phil Taylor (pectoral) for at least half the season.

"I"m always concerned about injuries," Shurmur said.

TE Moore returns to join fray: Evan Moore has a lot of catching up to do. He recently returned to camp after missing time with an undisclosed non-football related injury. But he's listed fourth on the depth chart behind starter Benjamin Watson, Jordan Cameron and Alex Smith.

Moore signed a contract extension last September after a strong 2010, but struggled with drops and blocking. Told that Moore admitted he needs work on his blocking, Shurmur said, "I'm glad they're repeating the stuff I tell them."

Watson has been sidelined in recent days, but Shurmur said he's expected back "very soon."

WR Massaquoi taking step forward: Asked who has made the most progress from last season, Shurmur didn't hesitate to cite WR Mohamed Massaquoi.

"He's totally different," Shurmur said. "He's having a fantastic camp. He came in healthy and with the right mindset. He's playing both inside and outside and is determined to have a good year."

Massaquoi is listed as a starter heading into the first preseason game. But he has more competition this year from impressive young receivers such as Josh Gordon and Travis Benjamin.

Shurmur said McCoy has a right to express his feelings: Shurmur defended the QB derby in camp, saying that all three "had a chance to show what they could do."

He was asked about it in the wake of negative comments made on Monday by Colt McCoy, who said he was told there would be a competition but intimated there was none.

"We're talking about a competitor," Shurmur said. "I didn't tell him what to say. He has feelings and he expressed them to you."

Stay dialed in on the Cleveland Browns on Twitter at @CBSSportsNFLCLE throughout the season with on-site updates from CBSSports.com RapidReports correspondent Marty Gitlin.