CLEVELAND -- Now is not the time for Felix Doubront to flounder.

The struggling Red Sox need the left-hander in the worst way. However, he has two losses and two no-decisions in his last four starts.

Boston was tripped up by the Cleveland Indians on Thursday, 5-3, in Progressive Field.

Red Sox manager Bobby Valentine said Doubront’s biggest problem was he couldn’t command his fastball. That’s not a good thing if you’re a fastball pitcher.

Tribe second baseman Jason Donald belted Doubront’s third pitch of the game into the right-field seats. Doubront (10-6, 4.70 ERA) said that didn’t lead to his undoing.

“I struggled in the fifth,” he said.

Doubront was rolling along with a 3-1 lead in the fifth when the Indians jumped all over him for three runs. He said he was settling in and had retired nine batters in a row. He said he wasn’t getting tired, just frustrated.

“My fastball is my best pitch,” he said. “It’s hard when I don’t have that pitch.”

The Red Sox had taken a 2-1 lead in the fourth on Adrian Gonzalez’s two-run homer, his 12th. Gonzalez has continued his assault on the American League since the All-Star break. In his last 31 games, he’s batting .412 (49-for-119) with 16 extra-base hits and 31 RBIs.

His 29 RBIs since the All-Star break is tops among AL batters and second in the majors to San Francisco’s Buster Posey’s 30.

Gonzalez is on fire.

Trailing by a run in the seventh, the Red Sox had a base-running gaffe that could have cost them a run. Second baseman Pedro Ciriaco led off the inning with a double. After Jacoby Ellsbury fanned, Carl Crawford grounded sharply to Indians shortstop Asdrubal Cabrera. Ciriaco broke for third and got in a rundown. He was tagged out by Cabrera, who wheeled and fired to second to get a sliding Crawford for a rare 6-5-5-4 double play.

Ouch.

Valentine said Ciriaco was a little overaggressive on the base paths. He also said that normally if Crawford was running hard the whole time, he can get to second safely on that play. He was, but he didn’t.

“The guy turned and made a good throw,” Valentine said.

The Red Sox had planned to take advantage of Indians starter Ubaldo Jimenez’s wildness. He came into the game leading the AL in wild pitches and walks. But Jimenez (9-11, 5.25) walked just one batter, didn’t uncork a wild pitch and struck out a season-high 10.

So much for that game plan.

“He was throwing the ball on the outside corner, low and away,” Valentine said. “He didn’t throw inside.

“(The umpire) was very generous on the outside of the plate. He was consistent.”

The Red Sox are now 12-15 since the All-Star break. Eight of those losses have been by two runs or less.