Nikita Zadorov's breakthrough season is done.

The Colorado Avalanche third-year defenseman fractured his ankle after falling during a 1-on-1 drill with Mikko Rantanen at practice Monday, and will miss the remainder of this season, the team announced.

Zadorov's injury happened in the first practice back for fellow defenseman Erik Johnson, who hasn't played since early December with a broken leg.

A key piece in the return for Ryan O'Reilly, Zadorov - a restricted free agent at the end of the season - has been a bright spot in an otherwise lost season for the Avs. He's seen a significant uptick in minutes over the last several weeks, and added an imposing physical aspect to his game.

With Johnson and Francois Beauchemin holding immunity thanks to their no-trade protection, the Avalanche must choose to protect four defenders to preserve two foundational pieces in the emergent Zadorov and veteran Tyson Barrie in the expansion draft.

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