MMAWeekly.com sources confirmed the bout first reported by MMAFighting.com.
The third bout in the trilogy between UFC heavyweight champion Cain Velasquez and challenger Junior dos Santos headlines the UFC 166 event slated for Oct. 19 in Houston.
Marquardt (32-12-2) won the Strikeforce welterweight championship in his first bout in the weight class. He lost the title in his next fight, against Tarec Saffiedine, and then lost his UFC return bout to Jake Ellenberger at UFC 158.
Marquardt at middleweight was consistently fighting at the top of the division during his first UFC stint.
Lombard (32-4-1), a former Bellator middleweight champion, has found it a rough road in the Octagon. He lost his promotional debut to Tim Boetsch, bounced back against Rousimar Palhares, but then faltered against Yushin Okami in his most recent bout.
He’ll be making his welterweight debut against Marquardt in a bout that is likely a must-win situation for both fighters.