With the game locked in a 4-4 tie, Avisail Garcia led off the bottom of the eighth with a fly ball to deep right against Boston lefty Andrew Miller. Nava drifted back, then settled for what looked to be a basket catch.
As Nava reached to his glove to throw it back in, the ball squirted out. Second-base umpire Mike DiMuro ruled it as a drop, and Garcia scooted to second.
"Yeah, I know I made the catch," said Nava. "You know, I'm not exactly sure on all the umpire rules as far as where everyone's supposed to be, but that's the ruling he made. It's unfortunate. But I know what happened, and that's what he saw happen. Obviously, he's human and sometimes calls go your way, sometimes they don't. That was just the case."
Fuming Red Sox manager John Farrell was ejected for his vehement protest of the call. It was Farrell's first ejection this season.
"When you spend the rest of the game in the clubhouse, you probably have a difference of opinion. Clearly, the call was missed," Farrell said. "He caught it. He went to transfer to his throwing hand, dropped it at that point.
"It wasn't like it was an instantaneous movement. He caught it in front of him, took it to his left hip to naturally throw the ball back in. He drops it -- he rules it a dropped ball, obviously. Kind of surprising, seeing it from the dugout. Three other umpires didn't see it either."
Nava and Farrell both hoped that DiMuro would get a different version from one of the three other umpires, and that the call would be overruled. But nobody had evidence conclusive enough to convince DiMuro to change his mind.
"To have a catch, you have to have complete control and voluntary release," said crew chief Ted Barrett, who was at third base. "Mike [DiMuro] had him with control, but did not have the voluntary release. When he flipped the ball out of his glove, he never got it into his hand. That's not voluntary release."
The argument could be made that first-base umpire Scott Barry would have had a better view of the play.
"Whether or not Scott Barry even saw the play happen, I couldn't tell you that," Farrell said. "That's probably a question that's better directed at them. And why it was called by the second-base umpire, I don't know. Whether or not that has an effect on the outcome of the game, it certainly changes the complexion of the eighth inning. We end up in a situation that we also contributed to, but we're in a much different situation with one out and nobody on base."
Barrett said that it's not uncommon for the second-base umpire to make such a call with nobody on base.
Almost predictably, things only got worse for the Red Sox after that controversial call.
Up next was Bryan Holaday, and he dropped down a sacrifice bunt. Miller picked it up and tried for the safe out at first. However, his throw was off the mark, and Dustin Pedroia -- who was covering -- was pulled off the bag. It was ruled an error on Miller. After Austin Jackson walked to load the bases, right-hander Alex Wilson came on to replace Miller.
The Tigers' Torii Hunter did his job, lofting a sacrifice fly to center to bring home the go-ahead run. Following an intentional walk to Miguel Cabrera, lefty Craig Breslow came on to face slugger Prince Fielder. That didn't go well either, as Fielder laced a two-run single up the middle.
The Tigers took three out of four in a matchup of first-place teams.
Though the Red Sox felt the Nava play went against them, they know they did a lot to beat themselves.
There were three errors, including the one by Nava. There was also a passed ball by Ryan Lavarnway that led to a run, and also another tough outing by Andrew Bailey, who gave up two hits and a run in his first outing since being removed from the closer role.
"With a lineup like that, you don't want to give them extra chances or things like that," said Pedroia. "We pride ourselves on playing good defense, so it's unfortunate when it happens."
Pedroia was involved in a strange play in the seventh. With Austin Jackson on first, Hunter hit a knuckling liner to second. Pedroia dropped the ball, and then threw to Mike Napoli at first. Napoli stepped on the base before tagging Jackson. If he had done the opposite, it would have been a double play.
It was one of those fluky plays you might not see again for years.
"I've never seen it," Pedroia said. "You don't know what to do. There was a lot of stuff going on. I was always told if you're a runner at first, you have to try to advance. When I threw, I think I was just yelling at Nap to tag everybody. He did."
Bailey then gave up a single to Miguel Cabrera, putting runners on first and second.
Lefty Andrew Miller tried to get his team out of the jam, but he gave up a single to Fielder to load the bases. On an 0-2 pitch with two outs, Miller hit Jhonny Peralta to force in the tying run.
"I'm disappointed. The first inning, I wish I'd made a little better pitch to Prince and got ahead there," said Miller. "I just kind of yanked that ball. It stinks -- you do all the hard work and get ahead 0-2, and you can't execute a pitch.
"The next inning, it's a tough way to start an inning. You get what you think is a first-pitch out, and you've got the nine-hole hitter, backup catcher, coming up next, and instead he's bunting. You get the bunt, I make a bad throw. I thought Pedey might have still been on the bag, but that's irrelevant. The throw has got to be better.
"Then Jackson, the thought process, I fell behind him, and once you fall behind, you need a strikeout and a ground ball, infield in, and it's kind of hard. I put us in a hole, and that's on me. That's a lot of stuff happening there. It's pretty disappointing."
It was a tough loss for the Red Sox, considering they ground their way to a 4-3 lead against Detroit ace Justin Verlander, making him throw 112 pitches in just five innings.
"Every game is tough to lose," said Farrell. "I thought we did an excellent job against Verlander. We had a number of opportunities that unfortunately we didn't cash in on. I thought our guys had a very good approach towards him."
Felix Doubront wasn't much more economical for Boston, throwing 104 pitches in his five-inning stint.
The Red Sox will use Monday's off-day to decompress, and then will open a nine-game homestand against the Rockies on Tuesday night.
"We've got to put today and this series behind us. We're still in first place," said Farrell.