BOSTON -- When Rangers pitcher Justin Grimm is at his best, he is a strike-throwing machine. So when he walked Red Sox outfielder Daniel Nava to open the first inning on Tuesday night, that was not a good sign.
Instead it was a warning for bad things to come as Grimm had a three-game winning streak snapped when he allowed eight runs in just 1 2/3 innings in a 17-5 loss to the Red Sox at Fenway Park. The Rangers were the only team to have not allowed 10 runs in a game this season. The loss also snapped the Rangers' five-game winning streak against the Red Sox going back to last season.
"I didn't have my fastball command and I didn't get ahead of hitters," Grimm said. "It was tough. Things just seemed to steamroll. I accept the responsibility for this loss."
The situation got so out of hand that outfielder David Murphy had to pitch the eighth inning. He held the Red Sox scoreless, the only time a Rangers pitcher did that in an inning all night. It's the sixth time in club history the Rangers have had to use a position player as a pitcher.
"Too many pitches in the middle of the plate and the Red Sox didn't miss them," manager Ron Washington said. "They came out swinging the bats and didn't stop until we put Murphy in there."
Grimm lost to Red Sox starter Ryan Dempster, who held his former teammates to three runs in seven innings. Dempster entered the game with a four-game losing streak and a 6.41 ERA in his last five starts. The Rangers' scoring off Dempster came on a two-run home run from Jeff Baker in the fourth and Nelson Cruz's 14th homer of the season in the sixth. Mitch Moreland later added a two-run home run in the eighth.
Reliever Joseph Ortiz, unexpectedly thrust into the role of long reliever, allowed six runs -- three earned -- in 2 1/3 innings. He gave up three home runs. Ortiz is expected to be optioned to Triple-A Round Rock before Wednesday's game to make room on the active roster for pitcher Alexi Ogando.
Rangers pitchers set a club record by allowing 13 extra-base hits. The Red Sox hit four home runs, including one by Mike Carp to lead off the fifth that right fielder Nelson Cruz just missed making a leaping catch in front of the right-center-field wall. Instead, Cruz went tumbling headfirst into the Red Sox bullpen, but came away unhurt.
"A lot of running tonight," Cruz said. "I don't remember the last time I ran that much. It was exhausting. We'll shake this off, come back tomorrow and try to put it together again."
The Red Sox scored two in the first and six in the second off of Grimm, who is now 5-4 while his ERA went from 3.93 to 5.13 in the span of 15 batters. Ten of those 15 batters reached on seven hits and three walks. Five of the seven hits were for extra bases, including a home run by No. 9 hitter Jackie Bradley. Grimm had not allowed a home run since his last loss to the Athletics on May 13.
Grimm said he looked at the video after he came out of the game and saw a mechanical flaw in his delivery. Grimm said he was rushing to the plate, leaving his arm dragging behind and that was causing his pitches to stay up in the zone.
"There's no need to overthink it," Grimm said. "That's an easy fix. I feel confident I can fix it."
Grimm has now made 10 starts on the season and it's obvious when he has his good command. In the five that he has won, he has walked two batters in 32 innings. In the four starts and a four-inning no-decision against the Mariners, he has 15 walks over 22 1/3 innings.
This was only the fifth time in 57 games this season that a Rangers starter failed to complete at least five innings and the first time since Josh Lindblom went 4 2/3 innings against Oakland on May 20. It's also tied for the shortest outing by a Rangers starter this season.
Nick Tepesch lasted just 1 2/3 innings against Seattle on May 20. Tepesch had to leave the game after getting hit by a line drive in his right wrist. Grimm just got hit hard.
"I didn't feel in control at all," Grimm said. "My fastball command wasn't there, some other things weren't there. It was just a lack of command and the Red Sox are really good hitters from top to bottom, whether you make good pitches or not."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.