That's No. 1 as in the catcher's sign for a fastball, a pitch that ultimately dampened Kirby's most recent start last Thursday at Kansas City.
A fourth-inning solo home run ended a stretch of 17 1/3 scoreless innings for Kirby before the host Royals pounced on his heater throughout a three-run sixth.
"I think I could have executed a little better (Thursday)," Kirby said. "If I didn't throw any fastballs, I probably would've done really well. ... They hit fastballs really well. We had a good game plan. That one inning just got away from me a little bit."
Seattle won the game 6-4 behind a five-RBI effort from Julio Rodriguez. The victory was the third during the Mariners' current eight-game tear, which continued Tuesday with a 6-3 victory against Chicago.
Winners of 16 of their last 19 games, the Mariners hold a one-game lead over the Toronto Blue Jays for the third and final American League wild-card spot.
Chicago harbored hopes of contention, too, but a disappointing season continued Tuesday not merely with the club's eighth loss in 10 games, but a front-office shakeup.
The White Sox announced before the game that executive vice president Ken Williams and general manager Rick Hahn were relieved of their duties. Both had served as club executives since the early 2000s.
"It was a surprise, to me especially," White Sox designated hitter Eloy Jimenez said. "But this is a business. They were really good to me. They helped me to get to this point, and that's why it really surprised me."
Chicago will turn to right-hander Michael Kopech on Wednesday as it tries to salvage a game from Seattle. Kopech (5-11, 5.12 ERA) is coming off a road loss to Colorado on Friday, when he allowed nine runs and six hits — including three home runs — in four innings.
Kopech is 0-0 with a 1.80 ERA in three career appearances (two starts) against the Mariners, with 13 strikeouts in 10 innings. Facing host Seattle on June 16, he took a no-decision after allowing one run and six hits in 4 1/3 innings, with six walks and four strikeouts.
Kirby (10-8, 3.23) got the start in Seattle's most recent bid for a nine-game winning streak before Wednesday. Facing the Baltimore Orioles on Aug. 12, he took a no-decision after scattering three hits and seven strikeouts in nine shutout innings. Baltimore won 1-0 in 10 innings.
Kirby hasn't faced the White Sox in his career.
Seattle has won 21 of its past 26 road games. A victory Wednesday would give the club a 9-1 road trip. The Mariners are set to begin a six-game homestand against struggling Kansas City and Oakland before opening September with another 10-game trip.
Seattle is 4-1 versus the White Sox this season after winning two of three games against Chicago in June.
—Field Level Media