BRISBANE coach Chris Fagan believes he has suffered a serious hamstring injury after taking part in Monday's Big Freeze 4 at the MCG.

Dressed as a reverend, Fagan was injured during the event to raise money for Motor Neurone Disease, alongside the 17 other AFL coaches.

After going down the slide, he jumped out of the pool of icy water and hurt himself.

"I might have done a serious amount of damage," Fagan told News Corp.

"I have done damage before and this feels no good."