If Jose Aldo cuts the line to a UFC title shot, the odds won’t be in his favor.

Aldo opened as a sizable betting underdog to UFC bantamweight champion Sean O’Malley for a potential matchup in odds released Monday by internet bookmaker BetOnline. The former two-time featherweight champion is listed as a +210 underdog, meaning a $100 bet on Aldo would return $210 if he pulled off the upset, while O’Malley sits as a -250 favorite.

Aldo, 37, returned from a near two-year MMA retirement this past Saturday with a vintage win over Jonathan Martinez in UFC 301’s co-main event, earning a sweep on the scorecards for a unanimous decision in his native Brazil. Aldo is now an MMA free agent but expressed a desire to challenge O’Malley for the bantamweight title if he re-signs with the UFC.

Aldo’s successful comeback reinserted him back into the upper echelon of MMA Fighting’s global bantamweight ranks, with Aldo debuting back at No. 6 on Monday’s update.

O’Malley, 29, is currently expected to defend his UFC bantamweight title next against top contender Merab Dvalishvili sometime this year. O’Malley remains a betting underdog (+185) in the potential fight against Dvalishvili (-220), but stands as a bigger underdog (+245) in a potential champion vs. champion match against UFC featherweight king Ilia Topuria (-285).