Colon, 23, showed symptoms of head trauma in his dressing room following his bout and was rushed to the hospital where he underwent surgery to relieve pressure on his brain, DiBella said.
Colon remained in critical condition on Sunday, according to DiBella.
An online video of the fight showed Williams, a 31-year-old fighter from Los Angeles, punching Colon in the back of the head in the seventh round, a shot that appeared to stun Colon, who was briefly examined in his corner. Williams was penalized for the illegal punch.
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Colon was then knocked down twice in the ninth round. He was disqualified after the ninth round his corner mistakenly took off his gloves, thinking it was the final round and that the fight was complete.
(Reporting by Brendan O'Brien; Editing by Alan Crosby)
