Pittsburgh Penguins defenseman Trevor Daley exited Amalie Arena with the assistance of crutches Friday after suffering a potentially serious lower leg injury as the result of contact along the end boards from Tampa Bay Lightning forward Ryan Callahan.

Head coach Mike Sullivan didn't offer an official update, but Sportsnet's Nick Kypreos reports the "initial fears" inside the organization is that the top-four defenseman suffered a fracture ankle.

Daley was significantly hobbled after the collision, unable to use his left leg as leverage to get back onto his skates.

His loss presents a massive hit to the Penguins, who have relied on Daley for 23 minutes per game throughout the postseason. He's also chipped in with six points in the offensive end.

Sullivan told reporters he will have an update Saturday.

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