Karl Alzner will miss his second straight game. (Patrick Smith/Getty Images)

TORONTO — Capitals defenseman Karl Alzner will not play in Game 4 against the Maple Leafs because of an undisclosed upper-body injury, Coach Barry Trotz said. Alzner also missed Monday night’s game, a 4-3 overtime loss, and he didn’t skate during the team’s optional practice on Tuesday afternoon. Washington is down in the first-round series against Toronto, 2-1.

With Alzner out, Nate Schmidt is expected to again take his place in the lineup. In Game 3, Schmidt skated on a pair with John Carlson, and he was on the ice for every Washington goal, assisting on the first goal of the game by Nicklas Backstrom. A goal by Auston Matthews in the first period went off Schmidt’s visor before falling back to Matthews’s stick for him to shoot the puck past goaltender Braden Holtby.

“My legs felt good,” Schmidt said. “Maybe get my head out of the way on the first one, but things like that will happen.”

Where Alzner’s absence was perhaps missed the most was on the penalty kill. Alzner blocked the most shots on the team during the regular season, and a strength is helping to clear the traffic in front of Holtby. The Capitals lost in overtime thanks to a power-play goal by Tyler Bozak in front. Washington’s defense, the stingiest in the league during the regular season, has allowed four goals in back-to-back games.

Before Monday night, Alzner hadn’t missed a game in seven years.