Letang will not be eligible to play in Wednesday's Game 4 of this hotly contested second-round playoff series. He was assessed a minor interference penalty for the hit on Johansson, which occurred at 15:41 of the first period of Pittsburgh's 3-2 win on Monday night.
Johansson returned to action in the game, which factored into the length of the suspension. However, he complained of a sore neck afterward and missed practice Tuesday.
"He'll be re-evaluated tomorrow, and we'll see where that is,'' Capitals coach Barry Trotz said after Tuesday's practice. "Other than that, I can't tell you a whole lot more.''
The Penguins are already without defenseman Olli Maatta, who is expected to miss a second straight game after he was leveled by former teammate and friend Brooks Orpik in Game 2. Orpik was given a three-game suspension for the hit on Maatta and did not play in Game 3.
"We'll prepare the same way," Pittsburgh coach Mike Sullivan said prior to the suspension being announced. "We're not going to change our style of play. We're not going to change our identity just because one guy comes out of our lineup.
"We've dealt with this all year. We've had guys go down with injuries for long stretches of time, important players. So I think our team understands how we have to play in order to be successful and will continue to work that way and prepare the way we need to."
Justin Schultz, who has played in one career playoff game, is expected to take Letang's place in the lineup Wednesday.
"You got to be in the game to know what it's like, but obviously it's a pretty intense series from watching," Schultz said.
Penguins defenseman Derrick Pouliot, who played in his first-ever playoff game in Game 3 because of the injury to Maatta, said other members of the defensive corps may see their responsibilities change with Letang's absence.
"Some of us we're going to have step up and take on some of the minutes that those guys eat up," Pouliot said. "We're still not going to change too much."
ESPN's Pierre LeBrun contributed to this report.
Letang's suspension could prove costly
Pierre LeBrun and Scott Burnside break down Penguins defenseman Kris Letang's one-game suspension and how it might affect the outcome of Game 4 against the Capitals. Letang was suspended for a dangerous high hit on Caps' Marcus Johansson.