SEATTLE -- Just as the Mariners’ rotation seemed to be finally getting healthy, Justin Dunn was placed on the 10-day injured list on Wednesday with right shoulder inflammation.

The transaction took place an hour prior to first pitch, with multi-inning reliever Robert Dugger taking Dunn’s roster spot, and one day after the Mariners activated No. 1 starter Marco Gonzales, who had been sidelined for five weeks with a left forearm strain.

Dunn was on the ROOT Sports telecast during the third inning of Wednesday’s game against Oakland to discuss his relationship with the late Pete Frates and the significance of the inaugural Lou Gehrig Day, which was celebrated across Major League Baseball as an effort to remember The Iron Horse and raise awareness for ALS research and education. Dunn was asked about the injury at the end of his interview.

“It’s all right. I just didn’t bounce back too good from the last one, but we’ll give it a couple days and hopefully we’ll clear it back up and be ready to go,” Dunn said.

Mariners manager Scott Servais said that Dunn shut himself down from playing catch on Wednesday as a precaution, and he’s hopeful that the issue is minor. Dunn first experienced pain when throwing on Tuesday, per Servais.

“I don't think it's going to be anything -- keep my fingers crossed -- maybe one of those where he just misses one start and we're able to calm it down,” Servais said. “Because talking to our training staff, [Dunn’s] strength is good. Everything like that is not an issue there. So maybe just a little inflammation in there, and hopefully we can calm it down and he only misses one start. But I'm not sure where that's going to go.”

The right-hander came one out shy of reaching six innings his last time out on Saturday against the Rangers, a 3-2 win in which he struck out eight and gave up just one run and two hits while walking two. Aside from Yusei Kikuchi, who is putting together a breakout season, a case could be made that Dunn has been the Mariners’ strongest starter.

He has a 3.18 ERA and 125 ERA+ (league average is 100). His one issue has been command -- he’s given up as many walks as hits (27) -- and length (he’s averaging right around five innings per start).

Dunn’s next turn through the rotation was scheduled for Friday opposite Shohei Ohtani in Anaheim, but the Mariners will now have to adjust. When Gonzales was shelved, the club used his turn as a bullpen day and were strategic with off-days to re-slot their starters to avoid the strategy as much as possible. It seems that Seattle will turn to a similar tactic at least this first time through the rotation.

Héctor Santiago is the prime candidate to give the Mariners length. He was stretched out to 75 pitches by the time he was called up from Triple-A Tacoma last week, and he tossed 2 2/3 innings on Tuesday, when he allowed five of six batters to reach during the seventh inning, which led to a six-run inning, and ultimately, a 12-6 loss.

Dugger was also leaned on in Gonzales’ stead to make abbreviated starts, basically as an opener. His most notable outing came on May 16, when he and the rest of the relievers collectively outdueled Shane Bieber in a 3-2 win. Paul Sewald can also gave the Mariners two innings, maybe more.

But even when the Mariners were able to cover innings on those bullpen days, there were lingering effects in the days before and after, with certain relievers becoming unavailable. The absences of Kendall Graveman and Drew Steckenrider, who remain on the COVID IL, loom large.

So, for the Mariners’ sake, hopefully Dunn’s issue is as minor as he made it sound when discussing it on Wednesday.