With the UFC women's bantamweight division now a sure thing in the wake of champion Ronda Rousey's successful first title defense, matches are steadily building up.
That bout was initially reported by German website GroundAndPound.de on Friday, with UFC officials providing confirmation to MMA Junkie shortly afterward.
Like Rousey, McMann is also an undefeated Olympian who's found early success in her transition to mixed martial arts.
Carrying a 6-0 winning streak since her May 2011 professional debut, McMann also has the marketable distinction of being the first American woman in history to receive a silver medal in Olympic wrestling.
Early Call: McMann or Gaff?
In addition to that accolade, McMann is also a multiple-time international wrestling champion who's earned medals in submission grappling during the FILA Grappling World Championships and ADCC North American Championships.
By contrast, Sheila Gaff's strength lies as much in her striking as it does in her submissions.
Boasting a nine-fight experience advantage, the German women's MMA veteran has scored nothing but first-round wins in all 10 of her career victories (out of 15 bouts).
With that addition, here are all the fights expected for the UFC 159 card:
• Jon Jones vs. Chael Sonnen
• Michael Bisping vs. Alan Belcher
• Al Iaquinta vs. Joe Proctor
• Nick Catone vs. James Head
• Jimy Hettes vs. Steven Siler
• Phil Davis vs. Vinny Magalhaes
• Cheick Kongo vs. Roy Nelson
• Jim Miller vs. Pat Healy
• Rustam Khabilov vs. Yancy Medeiros
• Ovince St. Preux vs. Gian Villante
• Sara McMann vs. Sheila Gaff
McMann and Gaff are both considered to be two of the top pound-for-pound female MMA fighters by several publications including MMA Rising—and with the UFC's female bantamweight division still being relatively small, this match could decide a future contender for Rousey.
Until that happens, the division's next No. 1 contender will be decided at the upcoming TUF 17 Finale card when former Strikeforce champion Miesha Tate takes on undefeated Brazilian Jiu-Jitsu black belt Cat Zingano.
UFC 159 kicks off on April 27 at Prudential Center in Newark, New Jersey. In the main event, light heavyweight champion Jon Jones will attempt to secure his fifth consecutive title defense against former middleweight contender Chael Sonnen. Also expected for the main card, both Michael Bisping and Alan Belcher will face off as they try to avoid back-to-back losses.