In a dramatic turn of events, heavyweight fighter Stefan Struve’s comeback at UFC 175 tonight against Matt Mitrione had to be cancelled at the last moment after he fainted backstage.

“They thought it was a panic attack, and they hooked him up to the machine,” Dana White told reporters, “but they’re taking him to do more tests.”

The incident is particularly troubling as Struve was returning after spending over a year on the sidelines due to a heart condition that had been discovered by doctors.

The issue threatened to end his career, but after being kept under close supervision by doctors he was allowed to resume training, and was eventually given the all-clear to compete again.

Tonight’s setback will once again throw his future into doubt, but the good news for now as that he’s apparently now ok, but they are not taking any chances so he will not be able to compete.

We wish him well and hope this is only a temporary setback.

As for UFC 175 – the main card now continues with just four fights.

Update:  Struve has now sent out a Twitter message to fans confirming that he is ok.

“Just want to let everybody know I’m ok, had a blackout in the locker room and we had to call the fight off, thanks for the love folks!