The Mariners’ best starting pitcher has now joined two of his fellow rotation-mates on the disabled list.

On Friday afternoon, the Mariners placed left-hander James Paxton on the 10-day disabled list with a left forearm strain, dealing another crushing blow to a starting rotation that has been without left-hander Drew Smyly since spring training and No. 1 starter Felix Hernandez since the previous road trip in Detroit.

“It sucks,” Paxton said. “Not what I wanted to happen, obviously. It’s one of those things that happens I guess. Luckily it’s a minor thing. It’s not going to be a long stint here. I’m hoping it will just be a couple of starts. I think three at the most that I will miss and I will be back.”

Paxton has been easily the Mariners’ best pitcher this season, posting a 3-0 record and 1.43 ERA in five starts. It was in that third win — seven shutout innings in Detroit on April 26 — that Paxton first felt some discomfort on the inside part of his forearm. It remained there in his start on Tuesday against the Angels.

“In Detroit, we had a long inning of hitting and I went out and I think I tried to ramp it up a little too quick,” he said. “I felt a little something. But I was fine and I went back pitching and everything worked out fine that game. It was a little bit sore, but throwing was fine throughout the week. In the LA game, it just got tighter and tighter as the game went on. Once I came out of the game, it was pretty sore.”

Paxton tried to play catch on Thursday for his midweek bullpen session, but the forearm felt tight. He notified manager Scott Servais and the training staff. And he was taken in for an immediate MRI.

“I just thought it was normal soreness after the Detroit game,” he said. “There was zero pain throwing. I didn’t think it was an issue. But in the LA game when it started to hurt when I was throwing, I knew something was wrong.”

The scan showed a Grade 1 strain of the forearm and no other structural damage, which was a relief for the Mariners.

“Fortunately, I think we dodged a bullet on this one,” general manager Jerry Dipoto said. “James has made really good decisions for all the time I’ve been here, from the way he prepared to what he’s been doing. The fact that he pointed this out to us this early we dodged a bullet. It’s a grade one forearm strain. There is no sign of anything else. The ligament is fine. There is no tear.”

Even with no structural damage, the Mariners will make sure he’s healthy before he returns. Paxton will be shut down from throwing for five days before restarting his throwing program.

“We don’t think this is a big or a long-term concern,” Dipoto said. “It’s more of a mild concern. But we are going to approach it cautiously because he’s very important to what we are doing.”

The hope is Paxton’s time away will be minimal.

“He will miss at least two starts,” Dipoto said. “We think in likelihood that’s what it will be — two missed starts. We’ll see him next homestand if we approach it the right way. So we are going to ballpark at two to three starts and two weeks.”

Paxton has certainly dealt with his share of injuries in his career, making trips to the disabled list in 2014 (lat strain), 2015 (strained finger tendon) and 2016 (left elbow contusion). But the trip last season was a fluke originating from a line drive off his pitching arm.

The Mariners will choose from either left-hander Dillon Overton or right-hander Christian Bergman to make Paxton’s scheduled start on Sunday in the homestand finale. Bergman is currently with Class AAA Tacoma, but will be recalled in the coming days. He’s scheduled to start on Sunday for Tacoma and is 5-0 with a 2.17 ERA in five starts. Bergman has 55 games of big league experience, including 11 starts, for the Rockies in the past. Servais will make the call on whether Overton or Bergman makes the start. It could depend on if Overton is needed for relief on Friday or Saturday night.

The Mariners called up right-hander Evan Marshall to replace Paxton on the 25-man roster. They also recalled infielder Mike Freeman and optioned outfielder Boog Powell back to Tacoma.

Freeman gives the Mariners more positional flexibility on their roster.