Through the first five innings, Rodriguez (4-5, 4.40 ERA) had managed the game well enough and his team was down 2-1 going into the bottom of the sixth.
In a two-batter sequence to start the inning, Rodriguez's night went south in a hurry. No. 7 hitter Chase Headley hammered a double. Then Greg Bird smashed a two-run homer to right on a fastball smack in the middle of the plate.
"I just thought he got into the sixth inning and his pitches started finding the center of the plate," said Red Sox pitching coach Carl Willis. "Prior to that, he'd gotten into a couple of situations and was able to get out of them. With Bird, he was trying to go away. But again, basically a fastball middle-middle, that's what big league hitters do."
Even with the defeat, the Red Sox still hold a 4 1/2-game edge in the American League East with 28 games to go. At some point, manager John Farrell will probably have to start plotting plans for a postseason rotation. For Rodriguez to be part of that, he'll need to become dependable again.
Chris Sale, Drew Pomeranz and Rick Porcello would be locks to be in the rotation in October. Things remain uncertain with David Price, who is just starting to throw off the mound again as he recovers from his second left elbow injury of the season. Doug Fister and Rodriguez would be vying for that fourth spot if Price doesn't have enough time to stretch back out as a starter.
Of late, Fister has been the more dependable pitcher of the two. It will be on Rodriguez to reverse that trend.
"You try every start to do better, that's all I'm thinking," said Rodriguez after giving up 10 hits and five runs over five-plus innings. "I'm not thinking about any game in the past, I'm thinking every time I get the ball, just get on the mound and try to put the team in position to win the game."
Putting the Red Sox in position to win was exactly what Rodriguez did before injuring his right knee in a slip in the bullpen at Camden Yards on June 1.
In his first 10 starts of the season (plus one relief outing), Rodriguez was 4-2 with a 3.54 ERA. In the nine starts since he returned, he is 0-3 with a 5.47 ERA.
When Rodriguez had a knee injury in 2016, he later admitted he was favoring it and thinking about it too much when he returned to action.
He is adamant that isn't the case this time, which makes his struggles all the more mysterious.
"It's not an issue," said Rodriguez of his knee. "I'm just missing pitches on the plate and it's something I'm working on."
The Red Sox don't think he's that far off if he can fine-tune his concentration and execution.
"He continues to work but he's still got a lot of work to do to be more consistent," said Willis. "He has to carry that game plan out, particularly tonight when you go out in the sixth, and you're in the bottom part of the order. It's a big inning to shut them down.
"He can still get there. He's overcome a lot of adversity with his knee, and back when he was younger and tipping his pitches. He's overcome things already and he has things ahead of him as any pitcher does. Regardless of how long you play, you have to continue to make adjustments."