Sacked tennis commentator Doug Adler is to sue broadcaster ESPN, claiming he compared Venus Williams' tactics to a 'guerilla', rather than a 'gorilla'.
During Williams' Australian Open second-round tie with Stefanie Voegele in January, Adler said: "Venus moved in and put the guerilla effect on."
Adler apologised after viewers complained, but was dismissed by ESPN.
An ESPN spokesman told BBC Sport: "We have not been served and are declining further comment."
Adler's lawyer David M Ring said that "guerilla tennis" was a common phrase in the sport to describe an aggressive match, citing a Spike Jonze-directed advert featuring Andre Agassi and Peter Sampras that was named after the term.