MINNEAPOLIS — Zack Wheeler is the Mets’ top trade chip heading to July 31, but that status was cast into question Monday when the right-hander was placed on the injured list with shoulder fatigue.

Steven Matz will move up a day and pitch in Wheeler’s spot Tuesday against the Twins, and team officials were still deciding on a plan beyond that. Jason Vargas could potentially return to pitch on full rest Wednesday, but the Mets would still need to slot in a starter during their upcoming four-game series in San Francisco.

Wheeler last pitched in the final game before the All-Star break, when he allowed six earned runs over five innings against the Phillies. The IL move is retroactive to Friday, meaning Wheeler would not be eligible to pitch until July 22 at the earliest. Wheeler’s injury, according to the team, was detected while he was preparing for his next scheduled start. The expectation, according to an industry source, is Wheeler will miss one or two turns through the rotation.

Several teams — including the Rays, Brewers and Yankees — have checked in recently on Wheeler’s availability, according to industry sources, but this setback could leave him stuck to finish out his season with the Mets, given that August waiver trades have been eliminated. Wheeler can become a free agent after the season, and if he leaves the Mets would obtain nothing for the pitcher unless they were to attach a qualifying offer to him. But such a scenario seems unlikely given that the Mets would be overpaying (the qualifying offer will be at least $18 million this winter) for a middle-of-the-rotation piece.

Wheeler has lacked consistency, going 6-6 record with 4.69 ERA, but teams remain intrigued by his 98-mph heat and high ceiling.

Vargas is another potential trade piece, but the veteran left-hander — who can become a free agent if the Mets decline his 2020 option — doesn’t bring the same kind of value to the equation. In recent days, general manager Brodie Van Wagenen has indicated the team is unlikely to trade Jacob deGrom or Noah Syndergaard, both of whom figure into next year’s rotation plans. Matz, who like Syndergaard is under club control through 2021, is also unlikely to be traded.

Even if Wheeler returns before the trade deadline, this IL move could hurt his value, resurrecting fears about his health. Wheeler missed all of 2015 and ‘16 rehabbing from Tommy John surgery and pitched only half of the following season, when he was shut down in July with weakness in his right arm.

His best season with the Mets was 2018, when Wheeler dominated in the second half. Overall, Wheeler finished 12-7 with a 3.31 ERA, which translated into him receiving $5.975 million in arbitration for this season.

Among non-pitchers, Todd Frazier is the most likely Mets player to be traded before the deadline. The veteran third baseman can also become a free agent after this season, and dealing him would allow the Mets to free up the position for Jeff McNeil and J.D. Davis, both of whom have been shifted to the outfield.

Wilson Ramos hasn’t been a terrific fit at catcher, and the Mets could look to deal him to an American League team. But Ramos still has another season remaining on the two-year contract worth $19 million he received last winter, which could make him difficult to unload.

— Additional reporting by Kevin Kernan