SEATTLE -- It’ll be months -- or maybe a year or two, realistically -- before the Mariners know if their “abbreviated start” plan with Yusei Kikuchi proves beneficial. But on Friday night against the Rangers, the first phase of the Kikuchi plan worked in the short term at least as Seattle topped Texas, 5-4, at T-Mobile Park.

Mitch Haniger won it with a bases-loaded, walk-off fielder’s choice grounder in the bottom of the 11th as the Mariners improved to 18-11, the second-best mark in the Majors behind only the Rays. The Rangers fell to 12-13 with their fifth straight setback. Haniger’s one-out grounder to third off reliever Kyle Dowdy scored Omar Narvaez, who had singled and moved up on walks to Ryon Healy and Dee Gordon.

When they signed Kikuchi in December, the Mariners unveiled a program in which they’d limit the 27-year-old free agent to one-inning starts about once a month this first season in the Majors to control his workload as he transitions from the once-a-week pitching rotation used in Japan.

The idea is to keep Kikuchi healthy for the long run, given the frequency of arm issues for many Japanese pitchers who transition to MLB.

Kikuchi breezed through his planned one inning, needing just nine pitches to retire the side in order with a pair of strikeouts. Kikuchi lowered his ERA slightly, to 4.54 through seven starts, but more importantly in the Mariners’ eyes, he will now be in better position to pitch stronger and longer this initial season in the Majors and beyond.

The second part of Friday featured the debut of Seattle’s top prospect Justus Sheffield, called up from Triple-A Tacoma to piggyback off Kikuchi’s shortened start. The Mariners were hoping to get 4-5 innings from the 22-year-old lefty, but Sheffield struggled with his command, walking four in a three-inning, 75-pitch performance in which he allowed a pair of runs on a Nomar Mazara home run off the batter’s eye in center.

“Sheff was anxious to get out there and wanted to contribute,” manager Scott Servais said. “He’s got things to work on yet. Controlling the strike zone is a big thing for us and he’s got to get more consistent there. He’s got pitches, he’s got weapons, he’s got stuff. There’s no question about that. He’s got to refine it a little more and get more in a groove like we saw early in Spring Training.”

The rookie, acquired from the Yankees in the James Paxton trade, considered it an important first step as he got his Mariners introduction out of the way. His only previous Major League experience was 2 2/3 innings in three relief outings last September for New York.

“I was just happy to get out there,” Sheffield said. “I had jitters early on, I will say. It’s been awhile since I pitched in a big league stadium. I just really wanted to keep the game close and pitch as deep as possible. At some points during the game, I was able to slow it down and make my pitches. It gets a lot easier when you get ahead and are able to attack guys. Once I was able to settle down a little, I felt a lot more comfortable.”

Thanks to a three-run blast by Edwin Encarnacion in the third, Sheffield turned a 3-2 lead over to Seattle’s bullpen and was in position for the win until Shin-Soo Choo’s homer off Anthony Swarzak pulled Texas back into a tie at 4-4 in the top of the ninth.

Encarnacion added a run-scoring single in the fifth in his four-RBI night and also made a huge defensive play when he got his glove up just in time to catch a line drive right at his face to get Swarzak out of a two-on, two-out jam and keep the game tied.

Encarnacion said the catch was a bigger play for him than the homer, as the ball was shielded by the baserunner, Elvis Andrus, until the last split second.

“The ball caught me,” said the veteran. “I saw it when he hit it, then I didn’t see it anymore. I just stuck up my glove and it worked.”

Battle of attrition in ‘pen
One of the challenges of the short start for Kikuchi is the added pressure on the bullpen, particularly with Sheffield only able to soak up three innings. Six relievers followed the two starters and Roenis Elias pitched the final two frames, even after throwing a 38-pitch inning in Thursday’s 14-2 win.

“We didn’t want to use him tonight, but it’s a nice weapon to have,” Servais said. “He has tremendous bounce-back ability. He threw 38 pitches last night and then is out there playing long toss today and is ready to go. Those guys are very, very valuable over the course of a Major League season. He’s having a great season for us. I appreciate his efforts.”

The Mariners had to burn through all their relievers except Chasen Bradford, but made it work in the end.

“Obviously we went through pretty much all our pitching staff tonight,” Servais said. “But we hung in. Our guys did a great job absorbing the innings, and we should be OK tomorrow.”