Pettis told ESPN on Thursday that he suffered a broken nose in the fight. His doctors said he did not need surgery but must rest for four-to-six weeks.
The 32-year-old Pettis (22-8) knocked out Thompson in the second round of his UFC welterweight debut two weeks ago in Nashville. In doing so, he became just the third fighter in UFC history to win a fight in three different weight classes (Kenny Florian and Conor McGregor are the others) and the first to knock out Thompson in his MMA career.
Pettis' next opponent isn't finalized yet, though he is hoping to return this summer.