DETROIT -- The Justus Sheffield conundrum continued on Thursday at Comerica Park. Would he have his elite wipeout slider, putting him in position to miss bats and set up his other two pitches? Or would he not, forcing him to play catch up? What about his two-seam fastball, which relies so heavily on precise location? Would the changeup be effective?

The results were mixed in an 8-3 loss that clinched the series for Detroit, which wrapped its 2021 slate against Seattle with five wins in six games.

• Box score

Tigers hitters were 1-for-8 against Sheffield’s slider, which at surface level sounds great. But the one hit was a booming homer from Jake Rogers in the third inning that sparked a lineup that was already out to an early lead, thanks to a first-inning homer on a middle-away two-seamer that Jonathan Schoop sent out for a solo homer.

Even so, the outs against Sheffield’s slider came off the bat loudly, and between all of his pitches, the Tigers tagged Sheffield for an average exit velocity of 95.2 mph on their 18 balls in play -- the highest such average of Sheffield’s career. For context, Statcast classifies anything 95 mph or higher as hard-hit, so essentially, Detroit averaged hard-hit contact throughout Sheffield’s four innings, which marked his shortest outing of the season. He’d gone at least five frames in each of his previous 11 outings.

“They're an aggressive club and they've got some power in their lineup, but I think Sheff just really didn't have much on the fastball and certainly didn’t have much command of it today,” Mariners manager Scott Servais said. “The changeup, you’ve got to locate when you don't have your fastball, certainly, [you need] your fastball command with your other pitches, and he just didn't have it today.”

Sheffield has now made more starts this year than in any single big league season of his young career. That itself is a milestone, but it also served as a reminder that coming into 2021, the Mariners were cognizant that there were going to be growing pains at times with their pitching staff. Beyond the 24-year-old lefty, many of Seattle’s young arms are navigating their first 162-game season.

“This year, I feel like it's been more of a roller-coaster season for me,” Sheffield said. “It feels like I'll have a good game and then I'll have a tough game. Next game, good game, then a tough game. So it's about finding that consistency. It's the big leagues, and I know it's gonna be tough at times, but I know that I'm fully capable of going out there and giving my all for my team and being a better pitcher than what I've shown so far."

Sheffield allowed five runs (three earned) on six hits and one walk over four frames. He has been stellar in Seattle, while his struggles on the road have become increasingly pronounced.

Home: 5 starts, 27 2/3 innings, 4-1, 3.58 ERA, .243 opposing batting average
Road: 6 starts, 31 innings, 1-4, 6.10 ERA, .331 opposing batting average

“Last year, I thought he was on a heck of a run. All 10 starts were very good, very competitive,” Servais said. “This year has been a little bit up and down. I know he is frustrated."

It’s worth noting that Sheffield’s defense put him in a hole on Thursday, with a pair of tough but critical errors to lead off the fourth inning that put runners on -- both of whom came around to score.

The first was a hard-hit grounder that chopped off third baseman Kyle Seager’s glove as he was going to his left side. The second was also hard-hit, but it was more playable for second baseman Donovan Walton up the middle. So instead of two outs and no one on for No. 9 hitter Willi Castro, Sheffield had runners on the corners. That led to a sacrifice fly instead of an inning-ending flyout that would’ve completed a 1-2-3 frame.

At the plate, the Mariners couldn’t get much going beyond a pair of impressive homers from Mitch Haniger, his 15th and 16th of the season, which pushed him into a tie for sixth place in the Majors. But both occurred when no runners were on base, which -- coupled with Sheffield’s tough day and three runs allowed by the bullpen -- forced the Mariners to play catch up all afternoon.

“I wish there was a good way to spin that game,” Servais said. “I don't think there is. We played a bad game.”