Maurer struck out four batters in his two scoreless frames, got into a brief stare down with Red Sox slugger David Ortiz and basically looked like a far more confident pitcher than when he'd last stepped on the Safeco Field mound in late May and lasted just four innings against the Angels while suffering his fourth straight loss.
Maurer was sent down with a 1-4 record and a 7.52 ERA in seven starts and immediately put into the bullpen in Triple-A Tacoma. He'd worked long relief at times as a rookie with the Mariners in 2013, but this time the club moved him into a late-inning role and he notched three saves with a 3.27 ERA in 11 innings over eight appearances.
The lanky Californian also started cranking up his velocity, freed from the need to pace himself over the long haul as a starter, and the results intrigued the Mariners enough that they brought him up for a look Wednesday when a roster spot opened with the demotion of Erasmo Ramirez following his own struggles as a starter.
Though Maurer's stay may be brief, given he likely will be sent back down on Monday when Taijuan Walker figures to be added to fill Ramirez's rotation spot in Houston, the 23-year-old already made a new impression with his initial relief outing.
"Holy smokes," said fellow reliever Tom Wilhelmsen, who preceded Maurer with three scoreless frames of his own after a rough start from Hisashi Iwakuma. "I think we've all seen it in the past. His demeanor just kind of says everything. He showed up tonight and I'm just really happy for him."
Everyone who's watched Maurer closely for the past two years knows he has a live arm and an arsenal of quality pitches, but for some reason that hasn't translated into consistent performances on the mound.
The thought now is for Maurer to just let it fly in short relief stints and eliminate the mental grind that seemed to be building as he struggled as a starter. And Maurer certainly isn't fighting that transition.
"It's fun," he said after Wednesday's outing. "Just attack, get back in the dugout and let our hitters put up some runs."
Does being a reliever perhaps better fit his personality?
"I think quite a bit more, actually, yeah," Maurer said with a smile.
Seattle's bullpen crew is an interesting mix, from bearded veteran Joe Beimel to the free-spirited Wilhelmsen to decidedly left-handed Charlie Furbush to crooked-cap closer Fernando Rodney to outgoing Danny Farquhar and talented youngsters Yoervis Medina and Dominic Leone.
Maurer brings a laid-back California surfer style to the mix, though his demeanor clicked into aggressor mode on Wednesday to the point where he found himself locked into a glare down with Ortiz before setting the veteran designated hitter down with some high-powered heat.
"We gave each other a nice little stare," Maurer said. "Competitive fun, I'd say. He stepped out because I was working a little quick and I just said, 'I'm not going to look away.'"
So, yeah, the kid figures to fit in just fine in a Mariners bullpen that has put up a 1.63 ERA over the last 39 games and currently leads the American League for the season at 2.64, which would be the best mark in club history if it holds up (a 3.04 in the 116-win season in 2001 is Seattle's best relief mark in franchise history).
"It is the coolest spot to be in the field," Wilhelmsen said. "It's a lot of fun down there. Good chemistry. The more the merrier. He fits right in."
What exactly does go on in the Mariners 'pen?
"We have a handshake for everything," Wilhelmsen said. "We sing a song when we walk out to the bullpen. We have discount double plays. We have everything you could possibly ever think of and more just pops up all the time. It's just something that comes and it's a lot of fun right now."
But one needs to perform to stay in that club for long, of course, and Maurer will have to back up his initial outing with subsequent performances if given the opportunity, either now or whenever a more-permanent opening arises.
If he continues unleashing the heat that froze the Red Sox on Wednesday, that chance surely will come at some point. Where exactly did the 97-99 mph fastballs come from in his return?
"I think that has to do with adrenaline, just knowing I can get out there and let it rip for an inning or two and let it go that way," he said.
Manager Lloyd McClendon is among those intrigued by Maurer's renewed potential as a reliever.
"I think it's a good role for him, as we speak right now," McClendon said. "There's a lot less to think about, a lot less preparation. You just go out and get it done and he did a good job."
Wilhelmsen dealt with difficulties of his own a year earlier when he felt the weight of the world on his shoulders after struggling for a time in the closer's role, so he understands well what mental stress Maurer has gone through already this season.
But just as Wilhelmsen has emerged with a fresh outlook and improved performance in a new role, he relishes the same opportunity for his young teammate.
"Every guy is different," Wilhelmsen said. "It's the big leagues and you're going to struggle. Hopefully he's had his and found his spot in the bullpen. I think it raised some eyes for everybody."