SEATTLE -- When Mike Clevinger went down with a teres major muscle strain, worry mounted over the sustainability of the Indians’ rotation, and rightfully so. Clevinger had been one of the most dominant pitchers in the American League since last year’s All-Star break and had picked up where he’d left off going unscored upon in his first two outings with 22 strikeouts.

That’s what makes what Shane Bieber is doing all the more valuable.

Bieber pitched six-plus innings of one-run ball in Cleveland’s 4-2 win over the Mariners on Tuesday night at T-Mobile Park, allowing just four hits and striking out five while giving the Tribe bullpen quality length after its starters struggled the last time through the rotation.

Most impressive on Tuesday, at least in the eyes of the Indians’ staff, was Bieber’s persistence and ability to adjust. Bieber felt out of sync early, particularly after walking Tim Beckham and Ryon Healy in succession during the second inning. That prompted a consultation in the video room, where fellow Tribe starter Trevor Bauer pointed out that Bieber was too rotational coming down from his leg lift and through the back end of his delivery. Bieber then returned to the mound focusing on being more linear with his mechanics.

“Just being able to have those guys and different eyes looking at your delivery, as long as you don’t get too mindful or dumbed-up about it, which I don’t think any of us do,” Bieber said. “I think it's a definite positive to have those guys having your back.”

Bieber walked one more batter and gave up two doubles before he was pulled in the top of the seventh, but in all, he pitched the Indians to a win for the third time in as many starts.

“I thought he battled his [tail] off,” Indians manager Terry Francona said. “I don't think it was his best command, but man, he battled. Shoot, the one inning, he walked two and almost walked a third. I don't think he's ever done that in his career. But he battled and gave us a chance to win.”

Even before Clevinger went down with the back injury that will keep him from beginning a throwing program for five to seven weeks, the Indians anticipated Bieber would take a significant step forward from his promising rookie season. He’s only 23 years old and debuted after less than two years in the Minors, yet Bieber has shown an acumen for attacking hitters and polish within his blossoming repertoire. This year, he’s turning to his slider and changeup far more to create more balance for himself and imbalance for opposing hitters.

After two punchouts and two hits surrendered -- which were still well-located -- batters are now just 4-for-28 with 10 strikeouts against his slider. His whiff rate (the percentage of misses against total swings) on the pitch this year entering Tuesday was a respectable 48.8 percent, up from 43.0 percent.

All of these factors are why the righty is turning to his slider even more this season, at 32.1 percent of his total usage, up from 22.6 percent.

“I think it's just more of being aware of what hitters are trying to do and I think just learning from my experiences last year, just trying to figure out sequencing and seeing if guys are sitting on sliders or curveballs and things like that, and just being able to keep them on their heels as much as I can,” Bieber said. “Really just a steady mix of everything is ideal.”

To punctuate his performance, Bieber remains one of the Majors’ most consistent starters on the road. Over 14 career road games dating back to his debut last May, including 13 starts, Bieber advanced to 9-0 and lowered his ERA to 3.12 in those contests. He’s gone scoreless in 27 of his last 28 innings away from Cleveland.

Offense backs up Bieber

Amid what’s been a quiet road trip at the plate, the Tribe logged a season-high 13 hits against the Mariners, including three from leadoff hitter Leonys Martin, who is hitting .414 over eight games on Cleveland’s road trip. Martin has three homers, a double, five RBIs, six walks and six runs scored in that stretch.

Carlos Santana also reached base for the 15th time in 17 games, going 1-for-4 with a critical RBI double that scored Jason Kipnis with two outs in the fourth, when the Indians took the lead for good. Santana is now 13-for-23 with runners on base, 8-for-14 with runners in scoring position and 6-for-8 with runners in scoring position and two outs.

Kipnis went 2-for-4 while batting third, giving the Indians’ middle infield production that they’ve needed while he and Francisco Lindor have been sidelined.