Instant Replay should not be used in Major League Baseball, unless it is for a very limited set of events. In the age of situational relievers and high offense, games are long enough as it is.
That said, using instant replay to review home runs down the foul line or instances of fan interference could add significant accuracy to umpiring while rarely slowing down the tempo of the game.
San Francisco Giants
As a lifelong baseball viewer with years of experience watching the game with instant replay, it remains obvious that in a significant number of situations, it doesn't conclusively resolve most of the disputed calls or close plays. That said, there is a place for plays that can be definitively called, such as foul line disputes, or plays where an umpire is not close enough to make a call, such as a fan leaning over the fence into play. In those limited situations, instant replay would be unobtrusive and helpful.
What is absolutely imperative is anything implemented must be implemented equally between the regular season and post-season. The games that actually win championships must always be taken as seriously as the games that determine who plays for said championship.
Toronto Blue Jays
Instant replay should be used in baseball during the regular season and during the playoffs, but only to determine if a ball was fair or foul, if it was a home run in cases were a yellow line is used, or when fans interfere.
Instant replay should not be used to review whether a batter was safe or out, or if a pitch was a strike or a ball.
St. Louis Cardinals
Sadly, the question of instant reply in MLB is totally irrelevant. I base that solely on the primary decision-makers involved. Think about it. When is the last time you read or heard anything about the QuesTec system? MLB is allegedly still using it for umpire evaluation based on data from a handful of ballparks, despite publicity hog Curt Schilling's child-like destruction of one of the machines back in his Arizona days in 2001.
The reason QuesTec has not been fully rolled out is the same reason instant reply would not be implemented any time soon. Among MLB ownership and the unions of the umpires and players, a change this radical to the tradition-driven game of major league baseball would simply not be agreed-upon. It just isn't going to happen because it isn't a priority for anyone to consider. In fact, I seriously doubt if there will even be a meaningful exchange of ideas and perspectives by the various parties who would have to concur. To me, that is the shame.
There is no place for instant replay in Major League Baseball. There are many Americans who aren't baseball fans because the games are too long, but I've never met a single person who boycotts baseball due to bad umpiring. Sure, there are small-market fans that subscribe to conspiracy theories about big-market teams getting all the calls. But these fans aren't so miffed by this notion that they stop attending games.
MLB is constantly working on better methods of evaluating umpires than what is currently in place. In this way, umpire accuracy can be improved upon without disrupting the flow of the game.
I am not in favor of using instant replay in Major League Baseball. The games are way too long as it is - without adding this headache. I would be in favor of limited use of instant replay in the playoffs and World Series - using it just to clear up a disputed home run - that is it.
I am in favor of closer scrutiny of the umpires and higher standards - which include reprimanding an umpire for shoddy performance.
Instant replay has no home in baseball. The human factor - on the part of players, managers and umpires - is part of the game and needs to stay as part of the game. Nobody involved with baseball is perfect and while umpires will miss calls from time to time, the old adage that things will even out over a long season is probably true.
Having said that, instead of instant replay, MLB needs to institute tougher standards for their umpires. No umpire should be safe if it can be shown that they have missed a certain percentage of calls and umpires deserve to be scrutinized just as much as players when it comes to their performance on the field.
Boston Red Sox
If you think a baseball game is slow now, just imagine how plodding it would become with instant replay. The beauty of baseball is in the spontaneity of its calls. There's no reason to mess with it.
Plus, as Tom Verducci pointed out in his excellent first-person account of a day as a major league umpire in Sports Illustrated, is umpires get it right almost all the time anyway. According to Verducci's article, Major League Baseball determined umpires made 100 incorrect calls last season--in 167,341 at-bats.
In addition, umpires have proven able to overturn a call on their own without the benefit of instant replay. Just look to game six of the 2004 American League Championship Series, when umpires correctly overturned two pivotal calls, including Alex Rodriguez' infamous slap play.
I am not in favor of using instant replay in Major League Baseball. Human error, like it or not, should be part of the game. That's part of the charm of sports -- or at least it was.
There are fewer personalities in clubhouses because everything is entirely too corporate. Why don't we just robotize everyone? That certainly is the way society is headed -- led by the biggest joke of all, the National Football League. Baseball, with its weak-kneed ownership that is interested only in making more money, will follow suit because they see the NFL's success as it panders to weak-minded fans. I despise instant replay ... but it is inevitable. Then again, so is the ultimate demise of the sport of baseball as it is presently mismanaged.
San Diego Padres
Call me nostalgic. I hated when the NHL changed the name of the divisions from Norris and Adams and Patrick to its current state lacking history. It will allow fans to better associate with the game they said. They were wrong.
The same holds true for instant replay in baseball. Unlike football, where there is so much action that is impossible for any sane man to officiate, baseball lives and dies by its calls, the battle its umpires have with the managers and taking second base and launching it into the outfield. Losing that means losing part of the game – the history of it. Where would we be today without the likes of Billy Martin and his affinity for kicking dirt? Playing hopscotch instead of watching baseball, likely. What a shame it would be if Joe Mikulik had no place in baseball, and instant replay would help ensure that. Keep instant replay out and the game of baseball – with its perfect flaws – intact.