News of the switch was first announced on Wednesday's episode of UFC Tonight.
Dollaway (13-4) puts his two-fight win streak on the line, having last defeated Jason "Mayhem" Miller and Daniel Sarafian. The 30-year-old holds a 7-4 record in 11 UFC contests since 2008.
Boestch (16-6), the UFC's No. 10 ranked middleweight, looks to rebound after losing consecutive bouts against Constantinos Philippou and Mark Munoz. Prior to his most recent setbacks, "The Barbarian" racked up a surprising four-fight win streak, knocking out Yushin Okami and outpointing Hector Lombard to submit his name into the 185-pound title discussion.
UFC 166 takes place October 19, 2013 at the Toyota Center in Houston, TX. An updated fight card can be seen below.