DETROIT (AP) -- Less than a week ago, the Detroit Tigers were rolling through the American League behind a terrific starting rotation.
By the time Thursday's game ended, their pitching had collapsed so badly that infielder Danny Worth took the mound for the final inning.
"Regardless of your team, you are going to go through a stretch where you don't get the starting pitching you need, and it taxes your bullpen, and things start to snowball from there," manager Brad Ausmus said.
This time it was rookie Robbie Ray who struggled, allowing seven runs in a 9-2 loss to the Texas Rangers.
Ausmus said the Tigers would call up right-hander Corey Knebel before Friday night's game, with a corresponding move to be announced to clear room on the 40-man roster.
Shin-Soo Choo homered and Chris Gimenez had four hits for Texas, which was without Prince Fielder. This was supposed to be Fielder's first game back in Detroit after the Tigers traded him in the offseason, but he could miss the rest of the season because of a herniated disk in his neck.
Yu Darvish (4-2) allowed two runs and six hits in seven innings, striking out six and walking three. The Rangers broke through quickly against Ray (1-1), who lasted only 3 1-3 innings. Ray allowed seven runs, nine hits and four walks, and the AL Central-leading Tigers lost their fourth straight.
Texas has won back-to-back games for only the second time this month, but the Rangers' injury woes remain a major concern. It looks like they will be without Fielder for a while, and in the third inning, center fielder Daniel Robertson hurt himself in an outfield collision. Robertson came diving in headfirst to try to make a catch, at the same time Rios came sliding in from right.
Alex Rios opened the scoring with an RBI double off Ray in the second, and Gimenez drove him home with a single. Adrian Beltre added a two-run double the following inning and later scored to make it 5-0.
In half of Darvish's first eight starts, the Rangers failed to provide a single run of support. That wasn't a problem Thursday. Choo's two-run homer in the fourth chased Ray, and Michael Choice's two-run single later that inning gave the Rangers a nine-run lead.
The Tigers lead second-place Minnesota by 41⁄2 games in the division, but they've allowed 31 runs in their past four games, an uncharacteristic spell for what might be baseball's best rotation.