Mets castoff T.J. Rivera getting chance with rival Nationals

T.J. Rivera’s agent initially was hesitant to let the former Met try to resurrect his career with the Long Island Ducks of the lowly Independent Atlantic League.

But it took only a month for Rivera’s decision to reject his agent’s advice to start paying off.

The 30-year-old Rivera signed with the Nationals on Saturday night, and will report to Double-A Harrisburg on Sunday, Ducks manager Wally Backman confirmed to The Post. Harrisburg allows the versatile infielder to be called up more quickly to the Nationals than if he were assigned to the Triple-A team in Fresno, Calif.

Rivera was released by the Mets in March without getting a chance to play in spring training to try to impress new…