He is out with a lower-body injury.
Letang, who is tied for second among NHL defensemen in scoring with nine points, is averaging 25:07 of ice time for the first-place Penguins. He had an assist during 25:19 in Tuesday's 4-2 victory at the New York Islanders and did not visibly appear to be physically hindered.
After he prematurely left the morning skate, Letang was not available to the media. Coach Dan Bylsma, as is his policy, did not comment.
"Game time (decision)," he said.
Matt Niskanen is out for at least another week due to an ankle injury, and Pittsburgh on Wednesday traded its seventh healthy defenseman, Ben Lovejoy, to the Anaheim Ducks for a 2014 fifth-round pick.
The Penguins recalled Pittsburgh native Dylan Reese from their American Hockey League affiliate in Wilkes-Barre/Scranton. Reese is making his Penguins debut against the Capitals.
"I think I know every bit of the system, so it's a smooth transition for call-ups and guys coming up and down," said Reese, who grew up just south of Pittsburgh in Upper St. Clair, Pa. "We play the same way in Wilkes-Barre as the team here, so I don't expect much of a transition period, so it should be nice."
Reese, 28, has three goals and 14 assists in 74 NHL games over the past three seasons, all with the New York Islanders. He was signed as a free agent by the Penguins in the offseason. He had three goals and 12 assists in 39 games for Wilkes-Barre/Scranton this season.
Letang was receiving Norris Trophy consideration last season until he was limited to 51 games due to injury. Twenty-one of his 31 missed games came following sustaining a broken nose and a concussion after a hit by the Montreal Canadiens' Max Pacioretty on Nov. 26.