SEATTLE -- Corbin Martin will be a part of the Astros’ long-term rotation, which is why the club believes that the growing pains of his rookie season could prove to be a positive learning experience.

Martin labored through just three innings on Monday, on a night where a taxed Houston bullpen needed length from its starter. The Astros still pieced together a 4-2 win over the Mariners, their fourth straight in as many games on its six-game road trip, but Martin’s command issues continued to plague him. He threw just 42 strikes of his 76 total pitches while walking three.

• Box score

“When a guy throws that many pitches in that short of time, a lot of things are going wrong.” Astros manager AJ Hinch said. “It's a little bit of everything. It's not an easy league. It's not an easy league to adjust to. We've just got to keep working to try to find the solution and not get him overloaded.”

"As a manager, he did the right job with pulling me,” Martin said. “Of course, I want to keep pitching. But those pitches early in the game hurt the rest of the outing. … Just falling behind. That's usually not what I do. I'm usually an aggressive pitcher and I compete. I'm going to go right at guys.”

Highest percent of pitches thrown behind in the count, SP, 2019

Min. 250 pitches thrown* (173 SPs)

1. Ervin Santana: 38.0%

2) Corbin Martin: 37.8%

3. Felix Pena: 35.4%

4. Antonio Senzatela: 35.0%

5. Luis Castilla: 34.4%

*entering play on Monday

Martin is the Astros’ No. 5 starter currently, a spot that initially was occupied by Colin McHugh before he was moved to the bullpen and then placed on the 10-day injured list on May 21 with elbow discomfort. McHugh played catch on Monday at T-Mobile Park, but he didn’t have any significant update on his rehab.

The top of the Houston rotation -- Justin Verlander, Gerrit Cole and Wade Miley -- is as good as any in baseball. The Astros are hoping Martin can give them more length and harness his issues within the fast-paced environment of pitching in the Majors. He’s pitched just 10 innings over his past three starts,

“Long-term, he's really good,” Hinch said. “He's going to be a really good pitcher in this league. He's got stuff. He's got the right mentality. We've got to coach him a little better and get him out of this funk.”

Although Martin only gave up two runs on Monday, they illuminated what has been a prolonged struggle: homers.

After solo shots from Mallex Smith and Edwin Encarnacion in the third, Martin has now given up eight homers in 19 1/3 innings this season, for a rate of 3.72 per nine innings. The Rockies’ Kyle Freeland has the Major League worst among pitchers with enough innings to qualify, at 2.43.

Five of Martin’s homers have come against his four-seam fastball, which is touted as his best pitch, according to MLB Pipeline scouting reports, which list him as the club’s No. 4 prospect and the game’s No. 57 overall.

“I try not to be as mental as possible. Just try and focus on one pitch at a time,” Martin said. “On days like today, when you're battling to throw strikes, you can't really think about, 'Hey, this has to be a strike here.' So you know, it's frustrating of course, but at the end of the day, it is what it is and I have to just keep working and competing and throwing through the zone.”

Arm-side command, particularly to right-handed hitters, has been one of his more glaring issues, Martin said.

“I'm just leaking again, so it's frustrating,” Martin said. “I know what I'm doing wrong and I'm not fixing it right now, so we'll get into it. It'll come and I know that.”

Nonetheless, the Astros continue to win when Martin starts. They are now 4-1 in games he takes the hill, and on Monday, they can credit a three-run barrage against Mariners opener Cory Gearrin, a season-high four innings from left-hander Framber Valdez, all shut out, and another scoreless outing from Ryan Pressly, his 24th in 26 appearances, which lowered his ERA to 0.64.

Even on a night when they didn’t get the length they needed from their starter, when they faced an opener for just the seventh time (including 2018) and when they once again deployed a strung-together lineup, the Astros willed their way to a win.

Against Gearrin, Alex Bregman walked, Josh Reddick hit an RBI triple to the left-center gap, Yuli Gurriel drove him in on a groundout and Robinson Chirinos hit a 414-foot homer on a first-pitch fastball, his eighth in what’s been a breakout season.

"My plan was to swing early,” Chirinos said. “He's a guy that likes to throw his fastball first pitch, and after that, he'll start using his slider. After Yuli hit that ground ball, there was nobody on base, I was like, 'Alright, [Gearrin] is going to throw me a fastball first pitch, and he threw it where I was looking for it, and I put a good swing.”

The Astros also extended their second-best 61-game start in franchise history, at 41-20. Their best was in 2017, when they won the World Series. That season also started a stretch where Houston has dominated in Seattle. Since July of that season, the Astros have won 21 of 27 at T-Mobile Park, including Monday.