Mike Zunino sent Kennedy's centered, 2-2 fastball in the fifth inning to the next-to-last row of the second deck, nearly out of Safeco Field. It was tracked by Statcast™ at 116 mph.
That was one inning after Mitch Haniger hit the 16th home run this season off Kennedy, the Major League-leading 117th homer allowed by the Royals in 2018.
The blasts were enough to send Kansas City to its 20th loss in 25 games to the soaring Mariners in the opener of this three-game series.
Kansas City's pitchers have allowed 129 runs while going 5-20 this month. Now they are waiting to see how Kennedy (1-8) wakes up Saturday from the pain in his side that caused manager Ned Yost to pull him after five innings and three hits allowed.
Yost called taking out Kennedy "a precaution."
"It happened when I threw that last pitch to Zunino. I felt it grab," Kennedy said. "The rest of the inning it just stayed tight. The last couple pitches I was compensating for it. I knew I could still pitch with it, but the right thing to do was to say something.
"I mean, I would say it's pretty mild. But I think the real test is how I wake up [Saturday]."
The Royals couldn't put enough hits together to pick up Kennedy while facing Mariners starter Marco Gonzales (8-5).
Whit Merrifield led off the game with a single and got bunted to second on a sacrifice by Rosell Herrera. But Gonzales then picked off Merrifield at second base.
And with one out in the fourth inning, Herrera sliced a double that went off left fielder Denard Span's glove after a long run to the warning track. Mike Moustakas then lined a one-hop infield single off Kyle Seager's wrist at third base. But Salvador Perez swung at the second of consecutive changeups from Gonzales and hit into an inning-ending double play.
Moustakas' RBI single with two outs in the ninth kept the Royals from being shut out for the fourth time this month.
"He did a good job of kind of establishing in, getting us looking in, then getting us out away," Yost said of Gonzales. "We got as many hits as they did. But they outslugged us."
BONIFACIO RETURNS Jorge Bonifacio made his season debut after returning from an 80-game suspension for violating Major League Baseball's Joint Drug Prevention and Treatment Program. He started in left field, batting fifth and went 0-for-3 with a strikeout. More >
SOUND SMART The Royals have scored 53 runs in their 25 games this month, by far the fewest in the Major Leagues. The next lowest-scoring team in June entering Friday was Washington, which had 25 more runs than Kansas City. The Royals are on pace to end June with their worst batting average for a month in team history. It was .190 entering Friday, the worst in baseball.
The 1992 Royals hit .207 in April on their way to finishing 72-90.
YOU GOTTA SEE THIS With two Mariners on base and two outs in the bottom of the sixth, Herrera ran up and to his left on a ball Ryon Healy looped into short right field. Herrera caught the ball below his knee to prevent a possible two-run double and keep the game at 3-0 entering the seventh.
Herrera started in right field for the ninth time this season because Yost put Bonifacio in left field for his return game. Left fielder Alex Gordon had a day off.
Expect Gordon back in left field Saturday and Bonifacio in right, where he was for 92 games as a rookie last season.
UP NEXT Saturday is Turn Ahead the Clock Night at Safeco Field. Jason Hammel (2-9, 5.34) wouldn't mind turning his clock ahead, past June. He's lost all four of his decisions this month. He allowed nine runs, six hits and five walks in his last start, Sunday at Houston. Hammel faces Felix Hernandez (7-6, 5.10 ERA) beginning at 7:10 p.m. PT.
Gregg Bell is a contributor to MLB.com based in Seattle.