Those tricky calls aren't being farmed out to technology quite yet.
Major League Baseball says expanded replay is out for this year, with the goal now to put the extra looks in play for 2013.
Baseball had sought to increase video reviews this season to include trapped balls, fair-or-foul rulings down the lines and fan interference all over the ballpark.
The additional replay required the approval of MLB and the unions representing the umpires and the players.
"We weren't able to come up with an acceptable set of agreements between the three parties," MLB executive vice president for labor relations Rob Manfred told The Associated Press on Tuesday. "We hope we'll be able to do it in time for the 2013 season."
Baseball began using replay in August 2008 to let umpires check potential home run balls. The sport's new labor deal provided the opportunity to expand on that, though things will remain as is this season.
"If they don't have it ready, I'd like for them to hold back. You don't want to change rules in the middle of a season," he said this week.
"I don't think it really matters either way, I really don't. I don't think it's going to change the game. But just overall you would like to have the same rules Opening Day as you have in the middle of the season and the playoffs," he said.
According to several people familiar with the situation, all of them speaking to the AP on condition of anonymity because the sides had not reached agreement, there were several sticking points.
Umpires were concerned the television feeds they received to review calls were not equal at every ballpark. The umps get fewer looks in Oakland, for example, than at Yankee Stadium.
Also at issue is how calls would be made under expanded replay and who would ask for a challenge. Would umpires still make the final decision, as they do now? Or would there be an NHL-style conference room with an MLB executive making the ruling?
"Like in hockey? Whatever is quicker," said Granderson, the Yankees' star. "I'm sure there's an official scorer upstairs at every stadium, put them with them. Let them watch it."
"See all the angles. Signal down, whether it be a hand signal, verbal signal or radio signal, and then do it. I don't think you have to go inside and do it. Something like that," he said.
As part of the negotiations, the umpires would like something in return -- maybe additional retirement or disability benefits, or perhaps a seventh umpire for postseason crews so more umps could get a chance in October.
The players' union, meanwhile, wants to wait to weigh in until after MLB and the umpires reach an understanding. Trying to get all three sides to agree, however, has proved a difficult balancing act.
"I know they are trying to do some things to upgrade the game and that's been talked about," Thome, the Philadelphia slugger, said Tuesday.
"It's hard to say this will work or that will work," he said. "I think you have to experiment with it before you say, 'Hey, that will do,' because to be honest, and they've done a good job with it, you have to understand what it's going to be before you comment on that. You have to see how it plays itself out."