Koscheck and Ellenberger are among three fighters tied for the No. 7 welterweight ranking by ESPN.com.
Each fighter enters the bout seeking to rebound from a loss.
Koscheck (17-6) was on the short end of a split decision to Johny Hendricks on May 5.
Ellenberger (27-6) was knocked out in the second round on June 1 by Martin Kampmann. The loss ended Ellenberger's winning streak at six.