Grand Junction's losing streak hit a season-high five games Wednesday, when the Rockies issued six walks in an 8-5 loss at Billings.
The Rockies also fell below .500 at 26-27, 7-8 in the second half of the Pioneer League South Division.
Trailing 2-1, things imploded in the bottom of the seventh for Grand Junction's usually reliable bullpen.
Blair Calvo, who lasted only one-third of an inning, gave up a one-out single to Cash Case, then made an errant throw on a pickoff attempt. A wild pitch allowed Case to reach third, and Quincy McAfee drew a walk. Reyny Reyes singled to center to get the first run home, and after a visit from pitching coach Blaine Beatty, Calvo walked the next two batters, forcing in another run.
He was pulled with one out and the bases loaded, but Juan Mejia, who hadn't allowed a run since July 4, couldn't right the ship. He walked in one run, threw a wild pitch to get another Billings run home, and a passed ball scored another run, putting the Rockies in an 8-1 hole.
After Beatty went back to the mound, Mejia got a double play to get out of the inning, and the Rockies rallied in the eighth.
With rain falling, Christian Koss reached on an error, and Brenton Doyle hit a two-out, two-run home run, followed by a solo shot from Todd Isaacs, cutting the lead to 8-4.
Turner Brown singled and scored in the ninth on a sacrifice fly by Jack Yalowitz.
Starter Anderson Amarista took the loss, allowing two runs through six innings. Calvo gave up five runs and Mejia one.