Credit: Mary Holt-USA TODAY Sports

A host of roster spots opened up for the Mets on Friday evening. The team sent Jose Martinez, Jose Peraza, Corey Oswalt and Robert Stock were all optioned to Triple-A Syracuse, the Mets say, but all four declined the assignment and elected free agency instead.

Peraza and Martinez were both able to decline the assignment because they had accrued at least five years’ service time in the majors, and once you hit that benchmark, you can decline getting sent back to the minors. (Martinez still accrued a year of service time despite being on the 60-day injured list all season.)

The most significant of the four is Peraza, who performed well for the Mets in a bench role and in high-leverage spots. He had a 224 wRC+ with four extra-base hits and nine RBI 19 high-leverage plate appearances. His season virtually ended in mid-July when he suffered a fractured finger. He returned two months later, garnering just two starts and 17 plate appearances over the last three weeks of the year.

Oswalt’s Mets career, which has spanned 44 appearances (24 starts) and about as many trips between Triple-A and Flushing, seems to be over. Stock, on the other hand, made two just starts for the Mets this season when the team was depleted of starting pitching, and he tore his hamstring running out a ground ball in the second one.

The four players were all either arbitration eligible or still making the major-league minimum, projected around $3.2 million, according to MLB Trade Rumors. Martinez, Stock and Oswalt were all on the 60-day IL to end the year, so this nets the Mets just one 40-man roster spot. That, however, will be replaced and then some with the reinstatement of guys like Jacob deGrom and David Peterson from the 60-day IL. Close to a dozen spots will open up once several Mets players reach free agency after the World Series.

Speaking of David Peterson, Justin Toscano reports that the lefty is close to 100 percent following a foot injury he sufferent when recovering from an oblique injury.