Bruce exits early with back tightness

Jay Bruce had a roller-coaster day dealing with back discomfort that culminated with his departure from Tuesday night’s game.

The Mets outfielder was removed in the sixth inning of his team’s 9-3 victory over the Padres with “tightness” in the back and hoped he can return Wednesday.

“It was kind of all day offand-on and I just tried to keep it stretched out,” Bruce said. “I couldn’t get it to stay loose.”

Bruce indicated he has previously dealt with tightness in the back, but it hasn’t led to missing significant action. Bruce said the toughest part of the situation Tuesday was telling manager Terry Collins he needed to exit the game.

“I take a lot of pride in playing and being out there and coming every day and being part of the team,” Bruce said. “That’s why I was trying to wait it out.”

Yoenis Cespedes’ last step before rejoining the Mets is showing club officials he’s ready to resume the grind of playing left field.

To that end, the veteran outfielder is expected to begin a minor-league rehab assignment this week, according to Collins, before rejoining the club.

Cespedes, who has been sidelined for the last 3 ½ weeks with a strained left hamstring, continued a running program on Monday, according to Collins, and is hitting.

Travis d’Arnaud caught nine innings of Steven Matz’s rehab start for Triple-A Las Vegas — he finished 0-for-4 at the plate — and is close to rejoining the Mets, according to Collins. D’Arnaud hasn’t played since May 2 because of a bruised right wrist.

Hansel Robles was optioned to Las Vegas after a horrendous stretch with the Mets. The right-hander followed a career-best scoreless streak of 14 innings by surrendering 12 runs in his next three appearances.