Phoenix starting power forward Sancho Lyttle tore her ACL on Saturday night and will miss the remainder of the season, the Mercury announced Monday.
Lyttle, 34, signed as a free agent in the offseason and has averaged 7.9 points and 5.3 rebounds in 18 games for the Mercury this season.
She had also been a significant force, with center Brittney Griner, in strengthening the interior defense for the league-leading Mercury.