Salvador Perez and Mike Moustakas homered off emergency starter Rick Porcello, who took over when David Price went back on the disabled list because of inflammation in his left elbow, and the Kansas City Royals beat the Red Sox 4-2 Friday night for their season-high ninth straight win.
Boston has lost five of six and nine of 14, dropping out of the AL East lead for the first time since June 29 and falling a half-game behind the New York Yankees.
Price started the season on the DL and didn’t make his first start until May 29. The 31-year-old left-hander, winner of the 2012 AL Cy Young Award, is 5-3 with a 3.82 ERA.
Porcello (4-14), who had been scheduled to pitch Saturday, leads the major leagues in losses. He allowed four runs and six hits in seven innings.
Jason Vargas (13-4) gave up one run and five hits in six innings. Vargas, who had been winless in three starts since June 30, is one shy of his career high for wins, set in 2012 with Seattle.
Kelvin Herrera pitched a one-hit ninth for his 22nd save in 25 chances, getting rookie Rafael Devers to hit into a game-ending forceout after Andrew Benintendi’s two-out single.
Kansas City, which has rebounded from a 7-16 start, is 15-8 in July and on its longest winning streak since nine consecutive victories from last Aug. 14-23. The Royals have outscored opponents 67-27 during the streak.
Perez homered over the Green Monster in the second and Moustakas made it 4-0 in the fourth. He hit his 30th homer in his 92nd game, the fastest to reach the mark in team history, and he is six homers shy of the Kansas City season record set by Steve Balboni in 1985.
Jorge Bonifacio had singled leading off, and Eric Hosmer beat the shift with a single to left that put runners at the corners.
Three days after his big league debut, Devers went 1 for 2 in his first home game for the Red Sox. He doubled down the right-field line in the fifth and scored on Mookie Betts’ single, and at 20 years, 277 days became the youngest Boston player with a hit at Fenway Park since Mike Garman in 1969.
Chris Young tripled off Mike Minor leading off the seventh and scored on Sandy Leon’s groundout.