BOSTON — Mike Montgomery reached a pitching marker as he continues to be stretched out in the starting role.

The lefty threw 90 pitches for the first time since September 18, 2018, on Monday against the Red Sox at Fenway Park. Montgomery struck out a season-high seven batters, while allowing seven hits and four runs (two homers) over five innings in the Royals’ 7-5 loss.

Montgomery, who was drafted 36th overall by Kansas City in 2008, was pitching out of the bullpen for the Cubs when the Royals acquired him last month in exchange for Martín Maldonado.

Montgomery returned to the starting role with the Royals on July 19, when he threw 45 pitches over two innings (allowing five runs) in a loss to the Indians. From there, he tossed 64 pitches in five innings in a second matchup with Cleveland, followed by 78 pitches over 4 1/3 innings in his last outing, against Toronto.

He switched up his pitches during Monday’s outing — 24 curveballs, 18 four-seamers, 17 sinkers, 16 cutters, 14 changeups and one slider. Of Montgomery’s 15 swinging strikes, he drew eight of them with his curveball.

Montgomery has now thrown 90-plus pitches 21 times in his career.