Sarah Kaufman's return to MMA after her 54-second loss to Ronda Rousey on Aug. 18 will have to be delayed due to an undisclosed injury.

The all-women's Invicta Fighting Championships announced that Kaufman is off the Invicta FC 3 show on Oct. 6 in Kansas City, Kan., where she was scheduled to face Kaitlin Young.

This has led to changing two of the scheduled fights.

Young (7-6-1) will have a rematch with Leslie "The Peacemaker" Smith (3-2-1). The two fought on the first Invicta show on April 28, going to a majority draw in what was considered the show stealing fight of the night. Young, from St. Louis Park, Minn., is best known for losing to Gina Carano on CBS TV on May 31, 2008, in a bout that ended with a blood stoppage at the end of the second round. The fight is still the eighth-most watched live televised MMA matches ever in the U.S., being viewed by 5,508,000 viewers. Young's big claim to fame was a 30-second knockout win over Miesha Tate in 2007, and splitting two fights with Julie Kedzie. She is coming off a second-round choke loss to Liz Carmouche on the second Invicta show on July 28.

Smith's original opponent, pro boxer Kim Connor-Hamby (4-0) of Stuttgart, Ark., will now be facing Raquel Pennington (3-1), of Colorado Springs, Colo. Pennington is coming off a decision win over Sarah Moras at the last Invicta show.

Kaufman (15-2) is one of the biggest names in women's MMA. The 27-year-old native of Victoria, B.C., held the Strikeforce women's bantamweight title, beating Takayo Hashi to become the first champion on February 26, 2010, in San Jose. She lost the title to Marloes Coenen on Oct. 9, 2010, also in San Jose, in a fight she was winning until being caught in an armbar in the third round.

Strikeforce and Invicta have a working relationship so fighters under a Strikeforce deal like Kaufman are allowed to take dates with Invicta as long as it's approved and doesn't conflict with their Strikeforce schedule.