It will take place at UFC 167 in Las Vegas on Nov. 16.
The 31-year-old Lawler has caught fire since simultaneously returning to the UFC and dropping down one division to welterweight. In his two fights since, he's knocked out both Josh Koscheck and Bobby Voelker, wins that have allowed him to crash the UFC's official rankings at No. 9.
Prior to that, Lawler had struggled with consistency, losing five of eight fights while competing for Strikeforce primarily as a middleweight. But he’s been reborn since returning to the UFC, where he competed for a two-year stretch from 2002-’04.
MacDonald, meanwhile is No. 3 in the current rankings. The 24-year-old has captured five straight, including consecutive decisions over Jake Ellenberger and B.J. Penn. He's 15-1 overall.
The Lawler-MacDonald bout will take place underneath the welterweight world championship fight between Georges St-Pierre and Johny Hendricks.