With a date against one of baseball’s best starting pitchers looming Tuesday night, Chicago Cubs manager David Ross acted aggressively with his best reliever Monday night.

In the process, New York Mets manager Buck Showalter might have run out of time to be patient with some of his team’s struggling veteran hitters.

The Mets will look to Jacob deGrom to play stopper on Tuesday, when New York will host the Cubs in the middle game of a three-game series.

deGrom (5-1, 1.66 ERA) is scheduled to oppose the Cubs’ Adrian Sampson (1-5, 3.76 ERA) in a battle of right-handers.

The Cubs (59-82) played spoiler on Monday, when Javier Assad tossed six innings of one-run ball to earn his first major league win and Rafael Ortega and Zach McKinstry homered in a 5-2 victory.

Despite the loss, the Mets (89-53) maintained their 1 1/2-game lead over second-place Atlanta (87-54) in the National League East by virtue of the Braves’ 3-2 loss later Monday night to the San Francisco Giants.

The Mets had plenty of chances to mount a comeback on Monday but went 1-for-9 with runners in scoring position. They left the bases loaded while failing to score in the first, then repeated the feat in the eighth, when Jeff McNeil and Pete Alonso began the frame with singles in a 5-1 game before Daniel Vogelbach worked a walk.

After right-hander Manuel Rodriguez struck out Mark Canha, Ross called on rookie left-hander Brandon Hughes, who has emerged as a viable late-inning reliever over the past month. Hughes retired Eduardo Escobar on a shallow fly to center before getting Darin Ruf — a right-handed hitter pinch-hitting for left-handed-batting Tyler Naquin — to line out to right.

Hughes allowed Francisco Lindor’s two-out homer in the ninth before closing out his fifth save. All five have been recorded since Aug. 18.

“You try to mix and match and not go to him too early,” Ross said postgame. “(The Mets have) a really good pitcher on the mound (Tuesday), so going to try to grab this one when we could and extend (Hughes) a little bit tonight. We don’t always like to get too much out of him, everybody’s got to contribute down there, but to lock in this first win was important.”

Showalter spent most of his postgame press conference fielding questions about why he chose to go with Ruf — who has one hit in his past 35 at-bats — over rookie Mark Vientos, who was recalled from Triple-A Syracuse on Saturday after hitting 24 homers in 101 games.

Vientos, 22, went 0-for-5 on Sunday in his major league debut against the Miami Marlins.

Ruf, Naquin and Vogelbach were all acquired in separate deals ahead of the trade deadline to help shore up the Mets’ designated hitter and corner outfield spots. However, Vogelbach is 5-for-39 (.128) since Aug. 23 while Naquin is 8-for-51 (.157) since Aug. 12 and struck out in all three of his at-bats Monday night.

“That’s not what beat us,” Showalter said of Ruf’s pinch-hitting appearance. “We had an opportunity there with some other people that didn’t drive in people in that situation, either. But I understand how people like to dwell on one thing, and rightfully so.”

deGrom won his third straight start on Wednesday, when he allowed three hits over seven scoreless innings as the Mets beat the Pittsburgh Pirates 10-0. He is 2-3 with a 3.13 ERA in 10 career starts against the Cubs.

Sampson didn’t factor into the decision on Thursday after giving up one run over six innings as the Cubs fell 4-3 to the Cincinnati Reds.

He made his lone start against the Mets on July 17, when he surrendered two runs over 5 1/3 innings in Chicago’s 3-2 win.

–Field Level Media