McCoy still is experiencing headaches and having other symptoms from his concussion, sustained last week on an illegal helmet-to-helmet hit by Pittsburgh linebacker James Harrison.
McCoy, who had his head snapped back by Harrison's shot to his face mask, is not traveling with the team. Shurmur said there has been no discussion about putting the McCoy on season-ending injured reserve.
"He's still having some symptoms and that's why we sent him home," Shurmur said.
"He's disappointed," said Shurmur, who has spoken with Watson. "But it's the right course of action right now."
Browns tight end Evan Moore was disappointed Watson's season ended prematurely, but understood the choice.
"That's a big loss," Moore said. "All of us are really close with Ben. He's doing well. I don't know the ins and outs of how the decision was made, but I know when it comes to the head, it's not something you mess around with. So I think he not only has to think about himself but his family. And Ben's a smart guy, so I'm sure he wanted to go with the right decision."
Shurmur said Watson did not discuss the possibility of retiring with him.
Copyright 2011 by The Associated Press