SEATTLE -- Chris Flexen continued his fill-in work for Robbie Ray on Monday, and in many ways, looked the part of Seattle's injured lefty, buoyed by four dominant innings but bitten by a runaway frame that put the Mariners in a hole they couldn’t dig out from.

Couple the second-inning deficit against Flexen with the tall task of facing Milwaukee’s Corbin Burnes, who was Ray’s counterpart in winning the 2021 Cy Young Award, and Seattle played catch-up for most of a 7-3 loss to the Brewers on a cold night at T-Mobile Park.

Burnes exited in the sixth inning with a left pectoral injury, just after surrendering a deep flyout to Julio Rodríguez, who hit his third homer of the year in the 8th inning. Ty France then followed with an RBI double to easily score J.P. Crawford from first base, but that only trimmed Seattle’s deficit to 4-2. And reliever Penn Murfee, who took over for Flexen to start the seventh, surrendered a homer on his first pitch to Brice Turang before walking Christian Yelich,  and then gave up an RBI knock to William Contreras that put the game out of reach.

The loss snapped the Mariners’ four-game win streak after a sweep of Colorado, but the Brewers proved to be a far better opponent as an early contender in the NL Central.

“Very frustrating putting the team down in a hole like that and having to climb back like that,” Flexen said. “It's back-to-back outings that's happened, and I'm just not doing a good job of putting us in a position to win.”

After a 1-2-3 first inning, Flexen found himself in trouble immediately, giving up singles to Rowdy Tellez and Brian Anderson. Then, he allowed a 104.8 mph double to Luke Voit that found the left-field corner, scoring a run. After a popout, he surrendered an RBI single to Owen Miller and a run-scoring forceout to Joey Wiemer to cap the three-spot.

Everything that the Brewers connected for in that frame was middle of the plate and up. They also had two knocks in the sixth, both against his slider -- one that hung and another that Willy Adames dug out.

“I think it's just straight execution,” Flexen said. “I'm trying to go down-and-away and you miss middle-up, and it's supposed to be hit. And I missed middle-up a lot with that pitch a handful of times, and that's when they did the most damage.”

In between the run-scoring moments, however, Flexen was nails, retiring 10 straight with no runs -- illustrating bright spots and the value he can bring while Ray is sidelined.

But, as the self-critical Flexen pointed out, those moments are marred by the runaway innings -- just like last Tuesday at Wrigley Field. Flexen gave up seven runs in the third in an eventual loss to the Cubs, spoiling a night in which the Mariners jumped out to a 7-0 lead.

“I went from giving up eight to down to four, so I'd say it's a little better,” Flexen said. “No, all jokes aside, it’s hopefully trending in the right direction. I've still got some work to do."

These same challenges plagued Ray early last year, when he’d succumb to one inning of multiple runs and a high pitch count -- but would otherwise shove. It wasn’t until mid-June that he turned things around and was one of the AL’s more productive starters throughout summer.

But Ray was a $115 million free-agent signee in his first year with the Mariners, whereas Flexen is a proven innings-eater who can get outs. The Mariners don’t need him to be an ace, but rather, a serviceable placeholder until Ray returns from a left flexor strain that he suffered in his first start on March 31. Ray was to be re-evaluated on Monday after being shut down for two weeks. If all goes well, he could begin a throwing program.

To successfully fill his role in the interim, Flexen recognizes the need to limit extended damage like he has these past two starts.

“Flex has put good stretches together for us, and I think he's got it in him again,” manager Scott Servais said. “Again, for me, it was a step in the right direction. You look up, the line score is four earned runs, and you've got to do better than that, but I thought he threw the ball pretty well.”