Washington Redskins Coach Mike Shanahan expressed disappointment in cornerback and defensive captain DeAngelo Hall for costing the team with an unsportsmanlike conduct penalty against the Patriots and for quitting on a play that led to a long New England gain.

Hall, an eight-year veteran, racked up 20 yards in penalties on one third-quarter play, helping fuel a Patriots scoring drive that resulted in them taking a 27-20 lead.

Patriots wide receiver Wes Welker (83), right, drags Redskins cornerback DeAngelo Hall (23) into the end zone on the game-winning touchdown catch Sunday.(John McDonnell/The Washington Post)

The ball was placed on the Washington 46-yard line, and five plays later, Tom Brady completed a 37-yard touchdown pass to Rob Gronkowski.

Shanahan said the penalty would have been disappointing regardless of who committed it, but was especially disappointing because Hall is one of the team captains and is expected to set a good example. The coach said infractions like that test his patience.

“Especially when guys are in a leadership role, we understand that you have to keep your cool, regardless of if you like a call or don’t like a call,” Shanahan said. “That’s your job to handle yourself in a professional manner, and more importantly, not put your team in a hole by having a 15-yard penalty. That’s one of the things that I talked about to our football team. You make too many of those mistakes and you’re not with us.”

In the first quarter, Gronkowski made a diving catch at midfield and ran another 10 yards as safeties DeJon Gomes and Reed Doughty tried to tackle him. Hall ran up but slowed down before he got to the players and watched as Gronkowski broke the tackles and ran past him for a 49-yard gain. One play later, Brady hit Gronkowski on an 11-yard touchdown pass.

Hall said that he thought Gronkowski was going out of bounds and thought the play was ending. But Shanahan said the cornerback was wrong in not playing until the whistle sounded.

“Yeah, that was disappointing,” the coach said. “One of the things DeAngelo usually does is finish. A lot of corners don’t like to tackle. He’s one of the more physical guys in the league, and I know he was embarrassed by it, as well as our whole football team. You’ve got to finish when somebody’s in bounds, because sometimes things like that do happen.”

Hall has been assessed face-mask, unnecessary roughness and unsportsmanlike conduct penalties this seasonl. After an early season loss to Dallas, he criticized defensive coordinator Jim Haslett’s decision to call an all-out blitz rather than give Hall help with safety coverage to prevent a big play. Hall gave up a catch to Dez Bryant that set up the Cowboys’ winning play.

In light of fellow captain Trent Williams’s suspension for failed drug tests, Shanahan was asked how he handles captains who set poor examples.

“Yeah, if I thought a person wasn’t a leader for one example or another, I wouldn’t revoke it. The players vote on the captain,” Shanahan said. “But I think people would lose confidence in the captain if he kept making bad choices and bad decisions. A captain is a player that you want to lead your football team and play at a very high level. That’s why he’s selected as a captain. Now, saying that, everybody makes mistakes. That’s part of the process. You’ve got to keep your cool, you’ve got to keep your poise. Just because somebody throws a flag doesn’t mean he’s a bad guy. It means you have to keep your poise and you can’t cost your team a 15-yard penalty. You’ve got to put your team first. … That’s the game, putting your team No. 1, you No. 2.”