TORONTO -- Back and forth, the pendulum has swung for Blue Jays starter Trent Thornton over the past couple of months. On Saturday against the Mariners, he managed to find some middle ground in Toronto’s 4-3 loss by pushing through six innings at Rogers Centre.

• Box score

It wasn’t all clean for Thornton, who walked four batters and allowed three runs on five hits, including a home run, but the end result was much better than it could have been after the bullpen started to stir in the second inning. He also managed to work through those six innings on just 86 pitches, marking the third time in four August starts that he’s gone six in under 90 pitches.

The biggest hurdle for Thornton has been consistency. When he’s on, he’s looked like an exciting part of the present and future Blue Jays rotation. In between those starts, though, there have been too many short outings. On Saturday, Thornton recognized the problem just in time.

“He made a big adjustment. He was all over the place, honestly,” said manager Charlie Montoyo. “Four walks. He couldn’t command any of his pitches. He did find a way to keep us in the game, but then the last two innings, seven outs or eight outs, he made an adjustment.”

Thornton has been searching for the proper adjustment in all of these starts but, with so many moving parts in his delivery, it’s not always easy to pinpoint the cause right away.

“It was more of a mechanical adjustment with my arm just not being on time,” Thornton said. “I talked to [pitching coach] Pete [Walker] in the tunnel and kind of got things squared away. Once I was able to make that adjustment, everything felt a lot better from about the fourth inning on.”

Heading into Saturday, Thornton couldn't pitch a full four innings in five of his last eight starts. Those other three starts were impressive, of course, but those short outings have been taxing on the bullpen, especially now that the Blue Jays are leaning more heavily on the opener strategy. If Thornton can extract those final couple of innings and carry the momentum into his next start, he’ll set himself up for a steadier finish to 2019 without as many noticeable ups and downs.

“Today, I thought I was able to make the adjustment a little quicker and avoid the big inning,” Thornton said. “For the most part, I felt like I ended the game on a strong note, at least.”

Bo Bichette extended his on-base streak to 17 games to start his career with an opposite-field single in the first inning, giving him yet another Blue Jays franchise record. Later, Bichette launched his fifth home run of the season on a low slider that might have been out of the strike zone. Vladimir Guerrero Jr. left the game with left knee discomfort after cutting in front of Bichette in the second inning to field a ground ball and will undergo an MRI.

After Reese McGuire tied things up with a solo shot into the second deck in the seventh inning, Seattle third baseman Kyle Seager put the Mariners in front with a home run off the foul pole in right.