BOSTON (AP) — Clayton Mortensen pitched 2 2-3 shutout innings after Josh Beckett left with back spasms and the Boston Red Sox beat the Detroit Tigers 4-1 in a game halted by rain in the top of the sixth inning Tuesday night.

Detroit had the bases loaded with two outs when the tarp was rolled onto the field. The game was called 1 hour, 45 minutes later, giving the Red Sox their fourth straight win and sending the Tigers to their fifth loss in six games.

Mortensen (1-0) allowed one hit and three walks with one strikeout after being recalled earlier in the day from Triple-A Pawtucket.

Tigers ace Justin Verlander (11-7) gave up all four runs in the fourth inning when he issued two of his four walks.

Detroit scored in the first when Miguel Cabrera walked with the bases loaded on Beckett’s last pitch of the game.

The struggling right-hander had been the subject of trade speculation before Tuesday’s 4 p.m. deadline for non-waiver deals. He began the day 5-9 with a 4.57 ERA and a 1-5 mark in his previous nine starts.

Subpar seasons by Beckett and Jon Lester, who began 2012 as Boston’s top two starters, are two key reasons for a mediocre year in which the Red Sox have hovered near the .500 mark.

But Beckett looked like a different pitcher at the start on Tuesday in a game played entirely in rain.

He retired the first eight batters then got Omar Infante to hit a weak grounder to shortstop. Pedro Ciriaco charged the ball, but Infante beat his throw to first. Then Beckett fell apart, hitting Austin Jackson with a pitch and walking Quintin Berry and Cabrera.

Beckett then motioned to the dugout and the trainer came to the mound. He checked the left side of Beckett’s lower back and the pitcher walked slowly off the field.

Mortensen came in and ended the threat by retiring Prince Fielder on a fly ball.

Verlander, who had gone at least six innings in his previous 63 starts, gave up two hits through three innings before struggling as the rain became heavier in the fourth.

Cody Ross and Jarrod Saltalamacchia singled and, after Will Middlebrooks struck out, Kelly Shoppach walked to load the bases. Ciriaco tied the game with a lined single to right and Jacoby Ellsbury forced in the go-ahead run with a walk.

Carl Crawford then grounded a single that trickled by second baseman Infante and drove in Shoppach. And when Infante was slow retrieving the ball, Ciriaco also scored.

The Red Sox got another break in the sixth when the rain ruined an excellent opportunity for the Tigers.

Fielder led off with a walk and Delmon Young flied out. Franklin Morales replaced Mortensen and Fielder was forced out at second on Ryan Raburn’s grounder. But Alex Avila singled and, with the rain pouring, Jhonny Peralta walked.

And then the tarp came out.

Notes: The Red Sox obtained LHP Craig Breslow from Arizona for RHP Matt Albers and minor-league OF Scott Podsednik. Breslow was not with the Red Sox for the game, and Mortensen was brought up to replace Albers on the roster. … OF Ryan Sweeney was put on the 15-day disabled list after undergoing surgery Tuesday for a fractured knuckle on his left pinkie. OF Ryan Kalish was recalled from Pawtucket. … Verlander was 6-2 with a 2.47 ERA in his previous eight starts. … Boston is 2-0 on its season-long 10-game homestand.