The team did not disclose any details in a formal news release, but team chairman Dan Rooney explained in a comment to the Pittsburgh Post-Gazzette.
"We're extremely disappointed with this incident," Rooney said. "The Steelers do not condone violence of any kind, especially against women. These kinds of incidents reflect poorly on all our players and many innocent and good people are considered guilty by association, they get thrown into the pot, so to speak."
Wilson initially was arrested on March 8 for the assault at a restaurant in nearby Wexford, Ohio.
He joined the Steelers as a free agent before the 2005 season after spending his first four NFL seasons with San Francisco.
In three seasons with Pittsburgh, the seven-year veteran has totaled 81 receptions for 1,162 yards and two touchdowns.