From the Mets’ point of view, there is nothing questionable going on. They clearly think highly of Barwis, a former strength coach for the University of Michigan football team who now runs a fitness business called Barwis Methods in addition to working with the Mets.

And while the players are paying to train with Barwis in the off-season, the Mets point out that they are picking up a sizable portion of the travel and lodging costs and are directly subsidizing some of the workout fees. In addition, players can still work out at other parts of the complex and not pay anything to Barwis.

Last winter, the Mets sent a handful of players to train with Barwis at one of his gyms in Michigan. Those players paid, too. For the most part, they were prospects and unproven major leaguers fighting for jobs, and the Mets considered the camp successful. Looking trimmer, Lucas Duda had a breakout season in 2014, hitting 30 home runs. Wilmer Flores emerged as a possible starting shortstop. Juan Lagares won a Gold Glove in center field.

This winter, the Mets went a step further. They had an empty space at their spring training site that had been viewed as a potential second clubhouse if another major league team were to join the Mets at Port St. Lucie. Instead, the Mets fixed up the space and rented it out to Barwis, reasoning that more of their players might be open to working with him in Florida during the off-season than in wintry Michigan.

The arrangement has raised questions as to whether players, particularly those who are still trying to establish themselves, might feel they are not in a position to say no to working out with Barwis in the off-season, even though they have to pay for it.