The Texas Rangers have overcome a plethora of injuries to key players during their impressive run, and they may have to add another to the list.
Adrian Beltre (quad), Jurickson Profar (shoulder) and Geovany Soto (knee) are all on the disabled list, and leadoff hitter Shin-Soo Choo sat out Tuesday's game with a sprained left ankle suffered in the series opener.
Kouzmanoff, who entered Tuesday hitting .370 with two homers and 10 RBIs in 12 games in place of Beltre at third base, left in the middle of the fourth inning with back tightness.
Former Athletic Michael Choice, starting in place of Choo, drove in the go-ahead run with an RBI single in the ninth as Texas (13-8) rallied for a 5-4 victory and its seventh win in eight games.
Choo may be ready to play by Friday, but Kouzmanoff's status is uncertain.
''The cold weather got to him,'' manager Ron Washington said. ''We wanted to get him out of there before it got worse.''
Though their lineup is banged up, the Rangers haven't needed much offense when Perez takes the hill.
Perez (3-0, 1.86 ERA) has been especially impressive over his last two starts, giving up five hits in eight innings of a 1-0 win over Houston on April 13 before tossing a three-hitter with eight strikeouts to beat the Chicago White Sox 12-0 on Friday.
"If I continue to do what I'm doing, this could be a big year for me," said Perez, who has a 74.6 percent ground-ball rate so far after inducing grounders 61.8 percent of the time in 2013. "My sinker was working in the first inning, and after that I was able to throw the ball where I wanted it."
Washington has taken notice of Perez's ability to mix pitches in the right situations.
"He's just being consistent keeping the ball down," Washington said. "He's using his breaking ball, he's using his changeup and he's moving the ball around. He's attacking, he's getting quick outs and he's keeping the ball down."
Perez has struggled at times against the A's, though, going 2-3 with a 5.79 ERA over five starts. Yoenis Cespedes is 4 for 9 with a double and a triple off the left-hander, and he drove in a run Tuesday as Oakland (13-7) lost a second straight game for the first time this season.
''You think you're sitting in the driver's seat, and ... all of a sudden we're down by one," shortstop Jed Lowrie said. "You could kind of feel the wind come out of the sails there.''
Coco Crisp, Josh Donaldson and Eric Sogard also had an RBI apiece, and Josh Reddick had two hits. Donaldson is batting .324 while hitting safely in 14 of his last 15 after beginning the season 2 for 22.
The A's will look to avoid the sweep behind Sonny Gray, who is coming off a so-so start.
Gray (3-0, 1.80) has won three straight outings, but he wasn't at his best after giving up three runs and nine hits in six innings of an 11-3 victory over Houston on Friday. It marked the first time he's allowed more than one earned run this year, and he's 7-1 with a 2.08 ERA over his last 10 starts.
The right-hander has never faced Texas, which has won seven of the last 10 meetings in Oakland.