The Arizona Diamondbacks played without one injured starter and lost another during their 12-6 defeat against the Miami Marlins in Phoenix on Tuesday, more unkind news for their paper-thin playoff chances.

Hot-hitting Ketel Marte left the game with back tightness in the fifth inning, an injury apparently exacerbated when he slid safely into home in the third.

"We're going to have a precautionary MRI (Wednesday) to make sure structurally everything is OK," Diamondbacks manager Torey Lovullo said of Marte. "We think it is, but we want to make double sure."

Marte will be held out of Wednesday's series finale, Lovullo said, when Marlins right-hander Sandy Alcantara (5-13, 3.93 ERA) is to face Diamondbacks right-hander Mike Leake (11-11, 4.39).

Arizona shortstop Nick Ahmed was removed from the Monday game with a finger injury and was a late scratch Tuesday.

"(Tuesday) he talked about feeling fatigue and tightness in his low back," Lovullo said. "I'm not sure how it popped up. There are a lot of innings and a lot of moving parts between two positions, and I think it is just a buildup of inning time."

Arizona (77-75) is 5 1/2 games behind both the Chicago Cubs and the Milwaukee Brewers for the second NL wild-card spot with 10 games remaining and two other teams to pass.

The Marlins (53-98) are nearing the third 100-loss season in franchise history, but Alcantara, who turned 24 on Sept. 7, has been the among their brightest lights.

The win-loss record does not reflect the steps Alcantara has taken in his first full season in the rotation. The culprit is the Miami offense: Alcantara has received an average of 3.03 runs per start, the lowest among major league qualifiers and almost a run lower than No. 2 Jacob deGrom (3.83).

"He's been aggressive. He's really stepped forward," Marlins manager Don Mattingly said. "He still has room to grow in a lot of little areas, but I think he has gained some confidence out there. When he is aggressive with his stuff, it is as good as anybody's.

"For me, he's taken huge steps."

Alcantara is 1-3 with a 2.59 ERA in his past eight starts, with 36 hits allowed and 48 strikeouts in 55 1/3 innings. He already has logged a career-high 178 2/3 innings, but the Marlins do not plan to shut him down before the end of the season.

"The progression is nothing that anybody is concerned about," Mattingly said. "You look at his tougher innings, and he probably has the least of all our guys, as far as having innings when you are throwing 35 or so pitches and getting out of multiple jams. He's been the cleanest guy we have as far as how his innings have gone."

Alcantara has faced the Diamondbacks once, giving up two runs in six innings of a no-decision in the Marlins' 3-2 walk-off victory July 26. He is 2-5 with a 3.58 ERA in 14 road starts.

Leake, 2-3 since joining Arizona at the trade deadline, has made quality starts in three of his past four outings. Leake has given up 38 homers, tied with Detroit's Matthew Boyd for the most in the majors.

Leake is 6-2 with a 2.74 ERA in eight career starts against the Marlins, his second-best ERA against teams he has faced at least eight times. He is 5-2 with a 2.19 ERA in nine starts against Atlanta.

--Field Level Media