Yusei Kikuchi tossed a perfect inning in his role as the "opener" for the Seattle Mariners in their 11-inning, 5-4 win over the Texas Rangers on Friday.

The single-inning start is part of the team's experiment aimed at reducing the Japanese lefty's burden in his major league rookie season and easing his transition from Japanese baseball.

Kikuchi coaxed a groundout and fanned two with nine pitches in the top of the first at T-Mobile Park before handing off to top prospect Justus Sheffield, who was called up to make his Mariners debut in relief.

"Because the game went to extra innings, by the end I had frankly forgotten that I had pitched," he said. "That's how quickly it went. It was something I'd never experienced."

The 27-year-old, who had a history of left shoulder trouble during his tenure with the Seibu Lions in Japan, is expected to pitch only one inning about once a month in order to limit his workload throughout the season, while still starting on four or five days' rest.

"Naturally, as a pitcher, I'm thinking I want to throw over a 100 pitches every game," Kikuchi said. "But I'm grateful when I consider my body in the long term."

"Because it was only one inning, I threw with all my might, because I didn't want to regret anything afterward."

Seattle's strategy differs from other major league clubs which typically use relievers as openers to allow their starters a reprieve from the top of the opposing team's lineup.

Japanese pitchers have gained notoriety for getting hurt in their MLB debut seasons. Most recently, the Los Angeles Angels' 2018 American League Rookie of the Year Shohei Ohtani had to undergo Tommy John surgery to reconstruct the ulnar collateral ligament in his pitching elbow during his opening foray as a two-way majors player.

Kikuchi is 1-1 in seven starts this season, having earned his first big league win last Saturday despite allowing 10 hits and four runs in a five-inning effort.