West Ham will investigate claims that Andy Carroll and Darren Randolph were drunk on Tuesday afternoon.
England striker Carroll, 27, and Republic of Ireland goalkeeper Randolph, 29, had been on a club-sanctioned night out on Monday.
Pictures surfaced on social media on Tuesday of the pair, with users suggesting they appeared drunk.
A West Ham spokesman said: "The club is looking into these allegations and will deal with the players as we see fit."
Carroll interacted with fans throughout the day, at one point seeming to suggest that he and Randolph were out for coffee, and not drinking.