SEATTLE -- The last time Nick Margevicius started a Major League game was 14 months ago for the Padres, when he gave up nine runs on 11 hits in 1 1/3 innings in Coors Field. So, yeah, there was reason for trepidation when the 24-year-old took the mound for the Mariners in his rotation debut on Saturday night.

But Margevicius feels like a different pitcher now, and the Mariners saw a new-and-improved version as the young lefty threw 3 1/3 scoreless innings in his first start in place of the injured Kendall Graveman in an eventual 5-0 loss.

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It wasn’t a pretty night for the Mariners, as they managed just one hit while falling to 2-7 on the homestand and 5-11 on the season, but it was a pretty fair outing for Margevicius as he offset a low-90s fastball with a 70 mph curve and limited the Rockies to three hits with one walk while striking out three.

“We’ve talked about his fastball ticking up and he did a really nice job with all his pitches tonight, but I love the back-and-forth combo of the slow curveball and the rising fastball off that,” Mariners manager Scott Servais said. “He can make pitches and he’s certainly not afraid of attacking. I think he’s going to be a nice fit for our rotation going forward. He’s going to keep getting starts with Graveman being out. I like what I’ve seen so far.”

Because Margevicius had been pitching in relief and thrown just five innings in three prior outings, Servais kept the 6-foot-5 lefty on a strict pitch count and pulled him after 61 pitches. But while the Rockies proceeded to break the game open against Seattle’s young bullpen, Margevicius showed he’s definitely capable of filling a spot in the Mariners’ six-man rotation as he builds his arm up.

“Anytime you go out and put up some zeros, it’s something to build on moving forward,” Margevicius said.

Colorado had an even more impressive debut on its side, as Ryan Castellani held the Mariners hitless -- with just one walk and a hit batter -- in four innings before he also was pulled due to a pitch count in his first start in the big leagues. Shortstop J.P. Crawford finally ended the Rockies’ combined no-hit bid with a two-out single in the sixth off reliever Jeff Hoffman.

The Padres rushed Margevicius to the Majors last year, putting him in their Opening Day rotation as a 22-year-old even though he’d pitched just one game above the Class-A level in his Minor League career.

The results were predictable, as Margevicius went 2-6 with a 6.79 ERA, including 0-2 with a 16.55 ERA in three starts against the Rockies. Colorado hitters went 26-for-55 (.473) with four home runs in those three games.

But Margevicius went home last winter and worked on improving his velocity. A fastball that averaged 88.5 mph last year has increased to the 91-92 range this year, while his slider has improved as well.

“My slider was pretty good today,” he said. “It’s definitely different than it was last year. Obviously, the fastball felt a lot better as I’ve been working on it. All the things I saw today were the kind of things I’d seen in earlier outings this season.”

As for the slow curve, which he used to strike out standout shortstop Trevor Story in the third?

“That’s something I’ve been throwing since I got into pro ball,” he said. “I feel good with it. I’ve kind of learned how to use it to hitters and feel confident with it. It’s kind of a weapon for me.”

The only real damage Saturday came from Charlie Blackmon, who doubled and singled off Margevicius on the way to a three-hit, three-RBI game. Blackmon’s base hit off Margevicius was followed by a one-out single by Daniel Murphy. That brought rookie Anthony Misiewicz in from the bullpen in a tongue-twister of a pitching change, with Misiewicz quickly retiring Matt Kemp and David Dahl to end the inning.

The remainder of the game didn’t go as well for the Mariners’ bullpen, as Blackmon ripped a three-run double off rookie Joey Gerber in a four-run fifth and the Rockies proceeded to improve their National League West-leading record to 11-3.