Firas Zahabi: Joseph Duffy suffered concussion Saturday night

Joseph Duffy was forced to withdraw from his UFC Fight Night Dublin main event fight against Dustin Poirier due to a last-minute head injury.
According to Duffy's head coach Firas Zahabi, Duffy was injured Saturday evening -- seven days before the fight.
"He suffered a concussion on the last day of sparring," Zahabi wrote via text message to MMAFighting.com.
Zahabi, who said his fighters "always spar the week before" a fight, did not question the UFC's decision to remove Duffy from the fight. Th