This story was excerpted from Daniel Kramer’s Mariners Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

SEATTLE -- More frustrating than the left forearm strain itself, in Marco Gonzales’ eyes, was that he felt he was pitching so well at the time of the injury.

On the 15-day injured list since June 3, Gonzales was upbeat despite his injury when he reunited with his teammates at T-Mobile Park. He was in Seattle receiving treatment for the duration of the Mariners’ 2-6 road trip. The goal was mostly to get the inflammation down and begin rehab exercises.

Gonzales played catch for the first time on Sunday, did so again on Monday and will give it a go on Tuesday before resting on Wednesday to reassess.

“Very light, like nothing, no tension,” Gonzales said. “So I'm not really putting a timeline on it. I'm day by day, obviously. I just want to take this slow because I don't want this to be something that lingers for sure.”

Gonzales estimates that he suffered the injury in his most recent outing on May 28 against Pittsburgh -- not in one specific moment, but rather through a slow build-up.

“Between innings, it took a little more to get loose in my warmup pitches each inning,” Gonzales said. “I was noticing it as the game went on. I didn't feel more fatigued, but I felt some more tightness building in my forearm. I felt like, once I got it loose, I was fine. Obviously, the ball was coming out really well. I feel like I had been throwing harder [my] last couple starts, too, which may have been attributed to that.”

Despite an admitted “clunker” on May 17 in Boston and one other tough outing in Toronto on April 30, Gonzales has quietly put together one of the most productive seasons in Seattle’s rotation. Outside those outings, he posted a 3.17 ERA and the Mariners went 6-2 in those games.

“It's frustrating, because I felt like the ball was coming out of my hand so well,” Gonzales said. “I'd had a couple of good starts in a row and I felt like after the game, it was just kind of a knot; just a ball in my forearm.”

Gonzales and the Mariners have formed a structured plan to reacclimate him to throwing, but it’s all “delicate, and subject to how he feels every day.”

“These things can linger and lead to bigger issues,” Gonzales said. “So it's important to take this thing slow for sure.”

Any time a flexor, forearm or elbow is mentioned among pitching injuries, anxiety can mount immediately, given that those ailments are the most prominently linked to major surgery and recovery of a year or more. Take Robbie Ray, for example, whose initial prognosis from a left flexor strain was a five-to-six-week recovery, but it ultimately led to him having Tommy John surgery in May.

All arms are different, obviously, and the MRI that Gonzales received was reassuring. The left-hander, who underwent Tommy John surgery in 2016 as a member of the Cardinals, called his latest injury “very similar” to the one that sidelined him for five weeks in May 2021. He returned from that one and was a key cog for the Mariners down the stretch, posting a 3.60 ERA and leading them to a victory in 13 of his final 20 starts.

“It’s a big relief,” Gonzales said. “Going through Tommy John, going through the ligament surgery, I felt like, knowing what that felt like, I knew that I was OK structurally for the most part.”

In the interim, Gonzales’ rotation spot is being filled by rookie Bryan Woo, the club’s No. 6 prospect per MLB Pipeline and a big part of its long-term plans. But Woo’s workload will continue to be monitored closely throughout the season, and Gonzales is Seattle’s longest-tenured player, as well as an innings eater.

He won’t put a timeline on his recovery, but the prognosis -- and so far, the recovery -- has been encouraging.

“We're optimistic and cautiously hopeful. ... That being said, this rehab process is delicate,” Gonzales said. “It's something that when I do come back, I need to stay back. So that's that's the goal.”