PITTSBURGH — Sidney Crosby walked around the Pittsburgh Penguins practice facility on Tuesday, trying to encourage his teammates as they prepared to go forward in their increasingly caustic playoff series against Washington without their captain and the game’s most indispensable player.

The Pittsburgh star is out for Wednesday’s Game 4 while recovering from yet another concussion, this one coming from being cross-checked in the head by Capitals defenseman Matt Niskanen in the first period of Washington’s 3-2 overtime victory on Monday night.

Penguins Coach Mike Sullivan said Crosby will be evaluated on a daily basis going forward. There is no timetable for the two-time MVP’s return.

“He’s very positive and we’re very optimistic and we’re hopeful that we’ll get him back in a timely fashion,” Sullivan said.

The defending Stanley Cup champions lead the series 2-1, an advantage they built thanks in large part to Crosby. He scored twice in Game 1 and dished out a pair of assists in a blowout victory in Game 2 to give Pittsburgh control in a meeting of the longtime rivals who finished the regular season with the two best records in the NHL.

All that momentum vanished 5:24 into the first period Monday when Crosby was knocked off balance by Washington’s Alex Ovechkin as Crosby skated in front of the Capitals’ crease.

Niskanen, who played with Crosby for four years in Pittsburgh before signing with Washington in 2014, turned toward Crosby. Niskanen’s stick caught Crosby flush across the right side of the head and the defenseman kept his hands on Crosby as the star fell to the ice before skating away.

Crosby was on the ice for several minutes before slowly making his way to the dressing room under his own power. Niskanen received a 5-minute major and a game misconduct.

The league decided against holding a hearing to determine whether the hit should be subject to review from the NHL’s Department of Player Safety. Niskanen said following the game the hit was not intentional, with Coach Barry Trotz calling it “a hockey play.”

Crosby has dealt with multiple concussions during his career, including one against Washington in the 2011 Winter Classic that he needed nearly two years to fully recover from.