SEATTLE -- Marco Gonzales pitched past his three-inning leash and looked every bit his part as the Mariners’ No. 1 starter in a much-anticipated activation from the injured list on Tuesday. He was backed by early run support, highlighted by a 426-foot, "welcome back"-type homer from Taylor Trammell in his return from Triple-A Tacoma.

But a six-run inning from 10 Oakland batters against relievers Héctor Santiago, Paul Sewald and Daniel Zamora spoiled what was shaping up to be Seattle’s sixth straight win, as the Mariners fell to the A's, 12-6, at T-Mobile Park.

Here are three takeaways from Tuesday’s loss, which dropped Seattle back to .500, at 28-28:

1) Marco is back on track
Gonzales, who returned from a left forearm strain and made his first start in five weeks, needed only 50 pitches to match his season-high six strikeouts. The lack of a rehab assignment didn’t faze the veteran lefty, who gave up just two hits and one run on a middle-middle sinker that was clearly a mistake pitch, one that Matt Olson lifted for an opposite-field homer.

Other than that, it was a hugely warm welcome back for the 29-year-old, whose workload will continue to be eased up given the sensitivity of the injury. Mariners manager Scott Servais said pregame that Gonzales was likely only set to pitch three innings, but his economical pitch count and cerebral composure gave the skipper the nudge to send him out for the fourth.

“I thought he was really sharp, command was really good,” Servais said. “He used all of his pitches. He got into the curveball later in the outing and he was very efficient with his pitches. So to get four innings out of him, 50 pitches -- on a normal night, he probably would’ve gone seven innings in that game, maybe eight. He was going that good.”

The Mariners have sorely missed their ace, not just from a results and leadership perspective, but also for the innings he normally provides. The club was using his spot in the rotation as a bullpen day, which led to mixed results in those games given the unstable nature of the strategy, but it also had reverberating effects on players’ availability in the days immediately after.

“I feel like it's a normal build-up fatigue,” Gonzales said when asked if he felt tired going back out in the fourth. “That Spring Training, second or third-to-last start of that building up … I was anxious for sure. It's tough watching. Spending a few weeks on the IL can certainly give you some perspective, but yeah, it was nice to get back out there and compete for sure.”

2) Trammell makes an immediate impact
He knew it right off the bat, as did the 9,160 fans in the stands -- Trammell’s first hit back from a Minor League demotion was a booming, 426-foot homer to the pull side that left his bat at 104.3 mph.

“It felt really good. It was one of those things where it was like I kind of envisioned it right as I was about to go to the plate,” Trammell said. “I saw, you know, what he was throwing to the previous guys, just preparing, looking middle-away and I just turned on it. And it felt really good off the bat.”

Trammell also walked, lined out to center and nearly beat out an infield single in the eighth, hustling down the first-base line with a 29.5 feet-per-second sprint speed (for context, league average is 27.0 and elite is 30.0). Most notably, there were zero strikeouts for the 23-year-old, who had MLB’s highest K rate (min. 90 plate appearances), 42.3%, when he was sent down on May 13.

Trammell’s numbers on the daily Minor League reports jumped off the page, but his offensive adjustments couldn’t be adequately gauged until he returned to the big leagues, where he hit .157/.255/.337 over 95 plate appearances in his first stint of 27 games after breaking camp on the Opening Day roster.

3) The bullpen misses Graveman
The absence of Kendall Graveman was as glaring on Tuesday night as it's been since he last pitched on May 16, with a limited number of available arms to stop the floodgates that the A’s opened in the seventh. That inning, Santiago began his outing by striking out Matt Chapman on three pitches, but then allowed five of his next six batters to reach, with his only out coming at the expense of a sacrifice fly.

Sewald then followed by giving up a walk and two singles, at which point he was pulled for Zamora, who surrendered run-scoring hits to his first two batters before getting out of the jam. That trio had contributed all of 11 1/3 innings with Seattle this season prior to Tuesday.

“We were thin in the bullpen tonight,” Servais said. “We knew that going into it, but I thought we had enough to get through. We just couldn't get that final out there in the seventh.”

In Graveman’s stead, Mariners relievers had more than picked up the slack, leading the American League with 1.3 wins above replacement, per FanGraphs, and only one blown save in 14 games entering Tuesday. The Mariners are also without leverage arm Drew Steckenrider, who is with Graveman on the COVID IL.