The promotion confirmed the news on Thursday, following an initial report by MMAjunkie.com. The bout will take place at KeyArena in Seattle.
Lawler (20-9) will look to build off a major knockout win over Josh Koscheck at UFC 157 in February. The fight was Lawler's first in the Octagon since 2004 and marked his return to welterweight following a lengthy campaign at 185 pounds.
A 12-year veteran, Lawler is 5-5 in his past 10 appearances. During that .500 stretch, he's knocked out the likes of Melvin Manhoef, Matt Lindland and Koscheck. A loss to Ronaldo Souza in January 2011 cost him a chance at holding the Strikeforce titile.
Saffiedine (14-3) capitalized on his opportunity at the Strikeforce belt, defeating Nate Marquardt in the promotion's final main event in January. Saffiedine rides a four-fight win streak into the Octagon, all of which came via decision.