Pittsburgh Steelers QB Dwayne Haskins suffered "substantial" injuries -- including a knocked out tooth -- after his wife allegedly hit him during an altercation in Las Vegas ... this according to cops.
It's all spelled out in a police report, obtained by KTNV, in which cops say they were called to the Cosmopolitan on July 3 to investigate claims that Kalabrya Gondrezick-Haskins had attacked the NFL player in their hotel room.
In the report, cops say Dwayne told them the fight went down because his wife was disgruntled after he had gone to a nightclub with friends without waiting for her and the rest of the group.