He had been Furious George more often late in the season.
Happy George resurfaced for his final start of the season.
In the Mariners' last game of the year, George Kirby shut down the Texas Rangers over six dominant innings Sunday, ending his breakthrough season on the upswing before a crowd of 43,997 at T-Mobile Park.
"Super happy," said Kirby, who allowed three hits with no walks and seven strikeouts over 71 pitches. "Finished on a high note. Unfortunately, I wish it was in the playoffs, but we'll be ready for next year."
In his first full season in the majors, the 25-year-old right-hander went 13-10 with a 3.35 ERA. He walked just 19 batters and struck out 172 over 190.2 innings.
Kirby made his 31st start of the season Sunday and threw his 20th quality start, tied for the third-most in the American League.
He had 14 starts in which he threw at least five innings and did not walk a batter, the most such starts by a pitcher age 25 or younger in MLB history.
Kirby also unveiled a long-rumored new pitch — a knuckleball.
All season, Kirby has hinted that he might break out his knuckleball one time when no one expected it. He threw it on the first pitch of the fourth inning — after catcher Cal Raleigh called for it — and got a swing and miss from Texas star Corey Seager.
"I told you guys I always had it in the back pocket, and it was a great day to throw it," Kirby said.
He threw it on the day legendary knuckleballer Tim Wakefield died at age 57.
"George is George, and he is gifted," manager Scott Servais said. "He can do a lot of different things in multiple sports, but he also has an extremely devastating knuckleball. And it didn't surprise me that he threw it. The fact that he threw it to Corey Seager did surprise me a little bit."
Over his final two starts, Kirby combined for 12 shutout innings to beat the Astros and Rangers.
Before that, he had a rough stretch in six starts — five on the road — in which he'd had a 5.56 ERA. After a loss Sept. 8 in Tampa Bay, he vented his frustration about Servais' decision to keep him in the game in the seventh inning.
Overall, he said he's pleased with what he was able to achieve this season.
"I prepare myself really well during the week," he said. "I expected to throw around 200 innings. I love it. I love going deep in games. I love to give our team chance to win every time. I'm really glad how my splitter developed this year. I think I can take a lot of good things away from this year."
* J.P. Crawford finished with a career-high 94 walks, becoming the first player in Mariners history to lead the American League in walks. Texas' Nathaniel Lowe was second with 93.
* In 81 home games, this season the Mariners drew an average crowd of 33,215 at T-Mobile Park. The total attendance figure of 2,690,418 is the highest since 2005.
* Rookie relief pitcher Prelander Berroa struck out two batters in a scoreless seventh inning Sunday. Recalled from Class AA Arkansas before the game, Berroa, 23, made his second MLB appearance. His first came July 21 vs. Toronto.
* Trent Thornton and Isaiah Campbell pitched the final two innings to preserve the Mariners' 18th shutout of the season, the most in MLB this season and a franchise record. Campbell picked up his first career save.