Oshie had surgery Friday after he was injured when he boarded by Carolina Hurricanes forward Warren Foegele during the third period of Game 4 of the Eastern Conference First Round on Thursday.
Oshie, who did not play in a 6-0 Capitals win in Game 5 on Saturday, had two points (one goal, one assist) in the series.
RELATED: [Complete Capitals vs. Hurricanes series coverage]
The Capitals lead the best-of-7 series 3-2 and can advance to the second round with a win in Game 6 at Carolina on Monday (7 p.m. ET; NBCSN, SN, TVAS, FS-CR, NBCSWA).
"He's back home and rehabbing," Capitals coach Todd Reirden said Sunday. "That's obviously a tough loss for us, but we're prepared to go without him, as we saw last night. It's a tough situation for our team, but I certainly liked our response last night and was proud of our effort in terms of how we played and how we were playing with him in the back of our mind."
Reirden stopped short of saying Oshie will be out for the remainder of the Stanley Cup Playoffs, if the Capitals advance.
"Seeing as it just happened, I don't have an exact timetable," Reirden said. "I do know that T.J. Oshie is going to do everything he can, and we're not willing to put a timetable on it right now with regard to any time. Just lots of these things take a different course in terms of how they rehab and don't rehab. I just know that I can tell you about T.J., he's all-in at all times, and that's a great person to have around our room at the very least."
Oshie was fifth on the Capitals with 54 points (25 goals, 29 goals) in 69 regular-season games. He was fourth on the Capitals with 21 points (eight goals, 13 assists) in 24 playoff games when they won the Stanley Cup last season.
"There's not one person who can take T.J. Oshie's spot for all that he is as a human being, player on the ice, off the ice, all the stuff that he adds," Reirden said. "But what I did notice is that everybody picked their level up last night, and that's what we're going to need going into Raleigh (North Carolina) for tomorrow."
