Frazier, Swarzak set to make return from DL

The Mets have two more reasons to believe in a turnaround.

Third baseman Todd Frazier will be activated from the disabled list Tuesday, at the start of the two-game series against the Orioles, along with reliever Anthony Swarzak.

Frazier, who went 4-for-9 in a three-game rehab stint with Triple-A Las Vegas over the weekend, will be making his first appearance since suffering a left hamstring strain May 7.

Frazier, 32, has batted .237, with five home runs, in his first season with the Mets, who have gone 9-15 in his absence.

“We need to get some of our key pieces back,” said manager Mickey Callaway, also mentioning the injured Yoenis Cespedes. “We’re missing our two main righthanded bats, so the struggles against lefties have been real for a reason because we’ve been missing some key figures.

“Right now we’re just trying to hold the fort down until those guys get back, and then we’ll be in a good place ... and can start trying to get on a roll again.”

Swarzak, who has been out since March 31, will provide immediate depth for the majors’ 26th-ranked bullpen.

After posting a career-best 2.33 ERA last season, the 32year-old was signed to a two-year deal, but he appeared in just two games with the Mets, before suffering an oblique injury.

Swarzak made three appearances with Triple-A Las Vegas in the past week, going 2-0, while allowing three runs in 2 2/3 innings.

The Mets bullpen has combined for a 4.62 ERA this season, and allowed 30 home runs, which is tied for the third-most in the majors.

Over the past 11 games, the relievers have combined to go 1-8 with a 7.94 ERA, while AJ Ramos (shoulder) remains day-today, and hasn’t resumed throwing yet. Ramos has been out since May 26. Cespedes is scheduled to take “live at-bats” Tues- day afternoon for the first time since hitting the disabled list. The outfielder has been out since May 13 with a strained right hip flexor, and could return without a rehab assignment.

Noah Syndergaard threw a light side session Sunday for the first time since landing on the disabled list with a strained ligament in his right index finger, and is scheduled to throw to batters Tuesday. If there are no setbacks, he could return Sunday to face the Yankees.