Major League Baseball wants to start using instant replay to review home run calls as soon as Aug. 1. USA Today reported last week that MLB is in talks with the umpires union to hammer out a system that works for everyone to decide so-called boundary calls -- whether a ball is over the fence or not, fair or foul.

The ump's been under the hood 6 minutes, and now here's the ruling: Ball 2!

It's heresy! George Will says so, in a column with the earthy lead sentence "One must say it ain't so."

Then again, speaking as someone who would trade a finger or two for the NFL's promise to scrap instant replay forever: I think it might be a good idea.

I'm all about the human element, bad calls being part of the game, all of that. And I don't want to see baseball sink to the tedious depths of the NFL, an umpire ducking under the hood for seven or eight minutes four or five times every game to parse some call down to the nose hairs. Or basketball referees spending half their time at the scorer's table double-checking the clock or where a toe was on a 3-pointer.

But, conscious of all caveats about slippery slopes, why not get home run calls right? Umpires are a long way from the outfield fences, and those fences have gotten complicated in the era of throwback ballparks, with their advertising and funky angles. The latest push for replay comes on the heels of an odd rash of blown home run calls in the majors this season.

Home run calls are pretty clear cut. The ball either went over the fence or it didn't. Video replay is good at telling us which. And a home run is a huge, huge play in a baseball game. We're not talking about stopping the game to see whether one basket out of 80 in a game was worth two or three points, or if the ball-carrier's knee touched the ground an attosecond before the ball came out of his hand.

Checking the video to confirm or overturn a close home run call is akin to the NHL's policy of routinely reviewing goals where there's any question about whether the puck went in the net. Only it shouldn't happen nearly as often. There are goals that warrant a double-check in almost every hockey game. Each team might run into a questionable home run call once a month or so.

That's all I'm up for. Home run calls. Fair or foul when a homer's not at stake? Let the umps figure it out.

We have to watch out for the old slippery slope: I'm not supporting replay without some assurances that a few years down the road we won't be stopping the game every other inning to review that bang-bang play at first base, that called third strike on the backdoor slider on the black, that diving catch that might have been a trap.

And I'm not supporting it at all starting Aug. 1. You don't change the rules in the middle of a season, or in the heat of controversy -- lukewarm in this case -- over a series of blown calls. Talk about it in the offseason, see if everybody still thinks it's a good idea. If so, go ahead. Get home runs right, but leave the human element in the game.

One must be able to say, "Kill the ump!"