SEATTLE -- In baseball, things can change in dizzying fashion.

Fresh off a glorious weekend sweep of the White Sox where the Reds starting pitchers combined for a 0.98 ERA and 21 strikeouts over 18 1/3 innings, Cincinnati’s pitching crashed back to earth at T-Mobile Park on Monday in a 9-3 loss to the Mariners.

Free-agent pickup Frankie Montas (2-2) had one of the poorer starts of his career, walking five hitters, tied for the most he’s surrendered in a single game, over two-plus innings while allowing three hits and five earned runs. He and the rest of Cincinnati’s hurlers combined to give up nine earned runs on 10 hits and six walks.

“Frankie from the very beginning wasn’t able to find the strike zone, which is very uncharacteristic,” manager David Bell said. “I mean, Frankie’s a strike thrower and you could tell right from the beginning of the night that it wasn’t going to be his night. He continued to battle, he gave us everything he had.”

The bleeding started immediately for Montas, who threw 45 pitches in the bottom of the first, the most pitches he’s tossed in a single frame in his career. He walked J.P. Crawford and Julio Rodríguez to start the inning, then allowed a three-run home run by Jorge Polanco to put the Reds in an early hole. He then walked two more batters but got out of the frame without further damage.

Montas’ previous high-water mark for pitches in an inning was 38, which also came against the Mariners on Aug. 30, 2018, as a member of the A’s.

After a clean second inning, Montas’ day came to a close in the bottom of the third. He walked Polanco to lead off the inning and promptly allowed a two-run homer to Mitch Haniger, which made it a 5-1 game and ended Montas’ outing after 66 pitches.

It was only the second time in his career that Montas walked at five batters in a game, and Monday was his second straight tough start. After giving up just one total run over his first two starts, Montas has now allowed five runs in back-to-back outings (only three were earned in his last start).

While the Mariners offense had scuffled in the first few weeks of the season, gaining a bit of a reputation as a free-swinging club with the third-most strikeouts in the Majors (174), Seattle was patient on Monday, tying a season-high six free passes.

For Montas, a big part of the problem was that his signature splitter simply wasn’t the dominant pitch it usually is.

“I think today was probably the first day that I got no swings on my splitter,” Montas said. “But I’ve definitely got to tip my hat, they took some good pitches and they took some good swings too.”

Despite an uncharacteristic lack of control, Montas and Bell insisted that Monday’s performance was nothing more than one of those off nights that every pitcher occasionally has.

“Overall he feels good,” Bell said. “His arm feels great, which is really, after a game like that, for me it’s really all I care about. Making sure he’s healthy and feeling good at the end of the night.”

In the second, Jeimer Candelario shortened the three-run deficit with a 415-foot solo homer to center field off George Kirby, his second as a Red. Jake Fraley drove in the Reds’ second run with a check-swing RBI double in the fourth inning, then the third run with a solo homer in the seventh.

The Reds finished the night with seven hits, including four doubles and two home runs.

Nick Martinez didn’t allow a run in his first three innings of relief work, but then gave up an RBI single in the sixth inning to rookie Jonatan Clase, the first knock of his career, to make it 6-2. Seattle added three more in the seventh, with Luke Raley driving in a run with an RBI triple to make it a 9-3 game.

“I think it was just one of those days,” Martinez said. “They came out swinging, and with a team like that, they were kind of scuffling and they weren’t going to be scuffling the whole year. It’’s a pretty good lineup. Tonight was just their night.”

It was also a night that Montas will have flushed from his mind as soon as he left the ballpark.

“It was one of those outings where nothing was working for you,” Montas said. “You can’t do nothing about it but flip the page and move one to the next thing.”