Edgar Cabral finished 3-for-4 on Wednesday morning, but Clearwater could not overcome a five-run Charlotte first in a 6-4 loss to the Stone Crabs at Charlotte Sports Park.
Clearwater (66-68, 28-36) would need to sweep Dunedin in the final series of the season in order to clinch a playoff spot.
The Threshers spotted Serathony Dominguez (4-4) with three runs in the first inning to take the early advantage.
Mark Laird struck out but reached on a wild pitch, and Jose Gomez followed with a bunt single. With one down, Darick Hall pulled a single to right to score Laird.
Wilson Garcia reached on an error to load the bases, and Cabral's infield hit combined with an error on shortstop Lucius Fox scored two more to bump the Threshers ahead, 3-0.
Charlotte (68-63, 37-26) responded with a big two-out rally in the bottom of the first, putting up a five-spot to take the lead for good.
Fox led off with a double, before Dominguez struck out back-to-back batters. Those strikeouts were followed by a pair of walks which loaded the bases, and another base on balls to Thomas Milone pushed across the Stone Crabs first run.
Nate Lowe followed by launching a grand slam to left-center to open up a 5-3 Charlotte lead.
Clearwater managed to pull to within one in the fourth. Cabral and Carlos Duran opened the frame with a pair of singles, and Emmanuel Marrero bunted them into scoring position. Jose Antequera's grounder to second scored Cabral to cut it to 5-4.
The Stone Crabs got that run back in the bottom half off reliever Luke Leftwich, as David Rodriguez's sacrifice fly made it 6-4.
Leftwich turned in 3.1 innings of one-run ball, while Blake Quinn, JD Hammer, and Seth McGarry combined for four scoreless innings of relief.
Clearwater will enter the final series of regular-season play either three games or four games back of the Dunedin Blue Jays, pending the outcome of Dunedin's Wednesday evening finale at Florida.
Edgar Garcia (3-4) takes the hill against the Blue Jays in the opener at home on Thursday at 7 p.m. The game will be broadcast live on threshersbaseball.com beginning at 6:45 p.m.
This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.