An NFL spokesperson told Jill Martin of CNN on Monday the league is not looking to see if Gronkowski ran afoul of league gambling rules, saying: "We have no information that indicates a violation of the policy."
Earlier, Brian New of CBS 11 in the Dallas-Fort Worth metroplex, citing an NFL attorney, reported the league was investigating the tight end.
ESPN.com's Todd Archer reported an attorney for the NFL informed both Gronkowski and the NFL Players Association that the cruise could be in violation of the league's gambling policy. Sports Illustrated law expert Michael McCann noted the ship entering international waters wouldn't preclude the league from ruling against Gronkowski.
Some of Gronkowski's peers have criticized his participation in the event. Both Houston Texans cornerback Charles James and Pittsburgh Steelers running back DeAngelo Williams hinted at a possible double standard:
Fan Expo LLC was already involved in a lawsuit with the NFL after the league prevented players, including Gronkowski, from taking part in the National Fantasy Football Convention at The Venetian in Las Vegas, which was scheduled for last July.
"The NFL's gambling policy states that the league does not allow participating in any appearances that are held or sponsored by a gambling-related establishment," wrote ESPN.com's Darren Rovell.
According to Pro Football Talk's Mike Florio, Fan Expo LLC amended the lawsuit to specifically cite Gronkowski's party cruise:
NFL player Rob Gronkowski hosted a party cruise from Miami to the Bahamas on February 19-22, 2016. The four-day party took place on Norwegian Cruise Line, where Gronkowski's fans and attendees can take full advantage of Norweigan's famed 'Casinos at Sea.' Photos from the booze-cruise show fans gambling at the on-board casino. The NFL specifically knew about the party cruise and its ties to gambling for more than seven months leading up to the event; yet the NFL took no action to either discipline Rob Gronkowski or prevent the event from taking place.
A Texas judge granted the NFL a summary judgment in the case Monday, but the National Fantasy Football Convention will appeal, per Archer.