NEW YORK -- Noah Syndergaard is scheduled to start Tuesday night for the New York Mets, returning to a major league mound for the first time in two years and completing his long comeback from Tommy John surgery.

The team also announced that ace Jacob deGrom won't pitch again this season. The two-time Cy Young Award winner has been sidelined since mid-July because of an elbow injury that's healed, according to the club.

He's been throwing bullpen sessions recently, including a successful one Monday, with an eye toward a potential return this year. But with the Mets out of playoff contention, deGrom and the club agreed there's no sense in him starting a game even though he's healthy, manager Luis Rojas explained.

"Everyone is fully on board," said Rojas, adding that deGrom should have a normal offseason. "It's the right thing. I think coming back in spring training he'll be the Jake that we know."

Syndergaard was reinstated from the 60-day injured list and will start the second game of a single-admission doubleheader against the Miami Marlins at Citi Field. The skidding Mets announced the move about 2½ hours before the first game, which was started by Marcus Stroman.

The 29-year-old Syndergaard can become a free agent after the season, and the Mets must decide how much they want him back and whether to make him a one-year qualifying offer.

"We want to see him pitch," Rojas said. "The organization will benefit from watching him perform."

The right-hander's return comes too late to help the 2021 Mets, who were eliminated from the postseason chase last weekend. New York (73-82) led the National League East for three months but began to nosedive when the calendar turned to August.

Syndergaard, an All-Star in 2016, is expected to throw just one inning Tuesday night and could make another appearance before the regular season ends Sunday. He and the Mets initially targeted a June return, but his rehab progression was slowed by a sore elbow that caused him to be shut down in late May for a while and then a positive test for COVID-19 in late August even though he is vaccinated.

"I think he's going to give everyone here an idea where he's at," Rojas said.

Syndergaard made a pair of rehab appearances last week for Triple-A Syracuse, working one inning each time. He allowed one hit and struck out two over two scoreless innings.

On the advice of doctors, Syndergaard stopped throwing his slider when he resumed rehabbing this summer because they thought that pitch might have caused the elbow discomfort he experienced in the spring.

So on his own, Syndergaard decided to scrap his curveball for now as well. He said he thinks he can be effective -- at least in short stints -- with just his four-seam fastball, two-seamer and changeup.

"He's excited. He wants to get in there and compete," Rojas said. "It's been a long road. ... He worked really hard to get in this position."

It will be Syndergaard's first big league outing since Sept. 29, 2019, against Atlanta. He tore the ulnar collateral ligament in his right elbow at spring training in March 2020 and had Tommy John surgery later that month.

Syndergaard will serve as the Mets' 29th man for the doubleheader. To make room for him on the 40-man roster, catcher Chance Sisco was designated for assignment.

Once the hardest-throwing starter in the majors, Syndergaard arrived in the big leagues in 2015 and helped the Mets reach the World Series that year. He is 47-30 with a 3.31 ERA in 119 career games (118 starts), all with New York.