NEW YORK - Battered playoff contenders trying to regain their 2015 form will meet Tuesday night, when the New York Mets host the Pittsburgh Pirates in the opener of a three-game series at Citi Field.

The reigning National League champion Mets enter Tuesday having lost the final two games of a three-game series against the Milwaukee Brewers.

New York scored only nine runs against the Brewers and didn't score until falling behind 5-0 in a 5-3 defeat on Sunday in which the lineup featured just two Opening Day starters -- right fielder Curtis Granderson and center fielder Yoenis Cespedes.

First baseman Lucas Duda (back), third baseman David Wright (neck) and catcher Travis d'Arnaud (shoulder) are on the disabled list, while second baseman Neil Walker (back) and left fielder Michael Conforto (wrist) were scheduled to visit with team doctors Monday to follow up on injuries sustained during the Brewers series.

Shortstop Asdrubal Cabrera received a routine day off Sunday.

The Mets also played Sunday without manager Terry Collins in the dugout.

Collins, who is the oldest manager in the league at 67 years old, felt ill before the game and was taken to a Milwaukee hospital, where he was kept overnight for testing and observation.

The Mets announced on Monday afternoon that Collins was given a clean bill of health and was en route to New York, where he will return to the dugout on Tuesday.

"We've got some guys that are playing everyday that are banged up," said Mets bench coach Dick Scott, who filled in for Collins. "We get to go home now. Guys have a day off. I think it's coming at a right time."

The Pirates, meanwhile, have been outscored 37-17 during a five-game losing streak that began with a 6-5 loss to the Mets in Pittsburgh last Wednesday.

The skid has knocked the Pirates, who have participated in the last three National League wild card games, out of playoff positioning. They are 2 1/2 games behind the Mets in the race for the second wild card.

The Pirates also lost two of their best players during the losing streak.

Catcher Francisco Cervelli (broken left hand) and ace right-hander Gerrit Cole (triceps) were each hurt during Friday's loss to the St. Louis Cardinals.

Cervelli is expected to miss 4-to-6 weeks, but the Pirates hope Cole will miss only one turn in the rotation.

"We'll just find ways to continue to work, roll up our sleeves and get a little bit better," Pirates manager Clint Hurdle said Sunday. "That's what we've got to do individually and across the board."

The welcome day off Monday was the first for the Pirates since May 12.

"I think it would be against the law to play any more in a row," manager Hurdle said. "So yeah, good timing."

The Mets will send right-hander Jacob deGrom to the mound in Tuesday's opener. The Pirates' starter had not been announced as of Monday afternoon.

Right-hander Juan Nicasio, who was in line for the start, was pushed back after giving up six runs in an inning of relief and taking the defeat in Friday's 9-3, 11-inning loss to the Cardinals.