The two Albion forwards have not been charged by Dudley police who are currently looking into the incident.
Inspector Mick Gillick, of Dudley North police, said: "He alleged that he had been assaulted by two local professional footballers at the Waterfront and we are investigating the allegation."
The Baggies chief executive John Wile said the club was aware of the incident but said they would not make any comment regarding action against the players until the facts of the case were made clear.
"We would not condone any violence of any sort by anyone," Wile said. "But until such time as we have got official details and have made our own inquiries we are not in a position to comment further."
Roberts moved to The Hawthorns in a £2 million deal this summer but has yet to score for his new side, although his appearances have been limited due to a foot injury.
