by Ken Pishna – MMAWeekly.com (Additional reporting – Jeff Cain)
In a matter of hours, Thiago Alves has been scratched from his UFC 111 bout with Jon Fitch and replaced by rising contender Ben Saunders.

According to sources speaking to MMAWeekly.com, Alves had a pre-fight CAT scan that revealed a potentially dangerous issue with the fighter’s brain, and while doctors were reviewing the issue, he could not be cleared in time to fight at UFC 111.

With 24 hours to go until weigh-ins, it was speculated that there wouldn’t be enough time to find a replacement, but Saunders was ready to go for the preliminary card and agreed to step in against Fitch on last-minute notice, according to sources close to the fight.

“People are asking why Saunders? He called me and said he really wants the Fitch fight and I respect that and Fitch wants to fight too!!!!” UFC president Dana White later tweeted.

Alves and Fitch were set to rematch from a fight in 2006 when Fitch came out on top, winning by TKO.

Saunders (8-1-2) last fought at UFC 106 this past November, defeating Marcus Davis by knockout with a brutal assault of knees. He was scheduled to face Jake Ellenberger on the preliminary portion of UFC 111, but with Alves’ exit the UFC decided to shuffle the deck.

A lightweight bout between Kurt Pellegrino and Fabricio Camoes was expected to replace the Fitch vs. Alves fight on the live broadcast, but the Fitch fight will now return to the main card on pay-per-view.

(UPDATED at 3:20 p.m. PT, March 25 – with comment from Dana White.)