BOSTON — The Royals’ offense continued to show signs of life, but it wasn’t enough to overcome right-hander Jason Hammel’s shakiest start of the season.

Hammel gave up eight runs over 4 2/3 innings and the Royals fell to the Red Sox, 10-6, on a rainy Monday night at Fenway Park.

Hammel, who had a 2.33 ERA over his last four starts, was staked to a 3-0 lead in the first inning when the Royals took advantage of three walks and a hit batter by Red Sox starter Eduardo Rodriguez. But Hammel gave up a home run to Mitch Moreland in the second inning and then a grand slam to Xander Bogaerts in a five-run third.

Trailing, 6-3, the Royals fought back in the fourth on a hit batter, and RBI doubles from Alcides Escobar and Whit Merrifield.

Royals third baseman Mike Moustakas was hit in the right arm by a pitch in the first inning and later removed from the game. X-rays were negative and Moustakas was diagnosed with a contusion on his right lateral forearm. He is listed as day to day.