The Sun says the pair clashed directly after the 2-0 defeat at the Emirates.
Pulis ordered the players to report for extra training today.
The squad had originally been given the day off as it was their Christmas party in London on Saturday night.
Former England striker Beattie, 31, protested on behalf of his team-mates and it is alleged the pair had to be separated by a member of staff as punches were thrown.
The bust-up will put a huge question mark over the future of Beattie, who Pulis signed from Sheffield United last January for £3.5million.