Over his 6 2/3 innings, Rodriguez allowed six hits and was charged with three runs. He had four walks (one intentional) and three strikeouts, while throwing 100 pitches.
Hughes, meanwhile, surrendered just as many runs as Rodriguez in only one-third of an inning. Corey Hart followed Ramirez's double with a run-scoring single before Hughes retired Jonathan Lucroy.
Before Friday, Hughes had led the Majors by stranding 96 percent (25-of-26) of his inherited runners this season.
"He's probably pitched as well as anybody that we've got out of the 'pen. It's another situation where it's not what you want when you want it," Pirates manager Clint Hurdle said. "He got put in the blender tonight. We've all been in the blender at one time or another these last two weeks."
Besides the runs it scored, Ramirez's double was also damaging for Pittsburgh in that center fielder Andrew McCutchen slid for it and hit his left knee against the outfield wall. Play stopped for a few minutes so he could be evaluated, but McCutchen stayed in the game.
Shortly after, Milwaukee added what turned out to be a crucial insurance run with Hart's single. In the bottom of the ninth inning, the Pirates scored a couple runs on singles by Neil Walker and Michael McKenry off reliever John Axford. But with Kameron Loe pitching and two outs, Gaby Sanchez struck out, stranding the potential tying run on second and the winning run on first.
"We pushed it probably as hard as we could. That's a tough way to go down," Hurdle said. "You battle all night long, and you get out there, but you come up short. It's been dogfights for a couple weeks for us right now."
Milwaukee scored the game's first runs, when in the second inning Hart brought Ramirez in from first with a double to deep left-center. He then advanced to third on the first of two errors in the frame by Clint Barmes before promptly following Ramirez home on a single by Lucroy.
The Brewers' two second-inning runs marked the 19th time this month that Pittsburgh had allowed its opponent to score first.
The Bucs battled back in the fourth, tying the game when McCutchen's line-drive single to left scored Jose Tabata and Travis Snider. Tabata led off the inning with a single, and Snider followed with a double.
Pittsburgh plated another run in the seventh, as Barajas hit a solo shot into the left-field seats for his ninth home run of the season. The catcher went 2-for-3 on Friday after posting two hits on Tuesday in San Diego.
"It's coming around. It's been a struggle lately for me," Barajas said. "I'm trying to keep this going through the end of the season and hopefully I can become a little more of an asset at the plate than I have been."
Barajas was the only Pirates hitter to enjoy a multi-hit night on Friday. Like Rodriguez, Brewers starter Mike Fiers surrendered three runs in 6 2/3 innings. In addition to two walks, he racked up 10 strikeouts.
"Coming out and throwing a good game, especially against the Pirates, is huge," Fiers said. "Those guys, I think they came off a series where they weren't playing well, and I think they had that urge to come out strong against us."
If it weren't for Fiers' bunt single in the seventh inning -- the first hit of his Major League career -- the game's outcome might have looked a little different. Replace that dribbler up the third-base line with an out, and Ramirez may not get a chance to step in and alter the score.
"That's how you win games -- when you come through with those clutch hits, you're going to win a lot of ballgames," Ramirez said about his double. "Especially [with] the way Fiers threw the ball. You know if you give him some support, we're going to be all right."
The Pirates have dropped four straight games for the first time since June 12-15. On Saturday, they'll be looking to avoid losing five in a row for the first time since April 10-14.