E! News reported McCollough has subsequently accepted the "24" star's mea culpa.
"I am sorry about what happened that night and sincerely regret that Mr. McCollough was injured," Sutherland said in a joint statement with the designer.
"I appreciate Mr. Sutherland's statement and wish him well," McCollough responded.
Sutherland, who was charged with misdemeanor assault after the alleged incident, is due in a Manhattan court June 22 to answer the charge.
He is accused of head-butting McCollough after the two exchanged words at a party.
2014: The Year in Fashion [PHOTOS]