With one out in the top of the ninth inning of last night's World Series game 1, Texas Rangers third baseman Adrian Beltre stepped to the plate. Down by one run with an elite power hitter at bat, Texas looked for a moment to have a chance of getting back into the game.

That chance was squandered when Beltre swung at the first pitch from St. Louis Cardinals closer Jason Motte, a 96-mile-per-hour fastball, pounding the ball down into the ground. As the ball bounced toward third base, Beltre hopped around the plate, as if the ball had hit his foot and was therefore foul. Fox Sports announcer Joe Buck thought it was foul, too. The umpire thought otherwise, and as Beltre stood waiting for a foul call that never came, Cardinals third baseman Daniel Descalso threw him out at first base. Motte then induced right fielder Nelson Cruz to fly out, sealing the victory for St. Louis.

Thanks to infrared cameras Fox debuted out for the game, television viewers—but not the umpires—soon learned that Beltre was no faker. The ball really did graze his left foot [see video of the play below], as evidenced by a fleeting thermal signature from friction between the ball and the toe of his cleats.

The high-speed infrared camera system, known as Hot Spot, is new to baseball telecasts but not to sports. "Hot Spot is a camera that's been used around the world for cricket, both for television and for officiating," says Michael Davies, vice president of field operations for Fox Sports. "What we're doing for the World Series is investigating what kinds of thermal stories we can tell for baseball."

Fox has three infrared cameras working during the World Series: one in center field filming home plate, and two cameras on the side of the field trained on first and second base. The idea of using thermal imagery on the bases is to try to pick up something in a bang-bang play that ordinary color cameras cannot see. "Maybe we would see a tag ahead of a runner sliding," Davies says. "Last night there wasn't a lot of that. You could certainly see the hot spot off of the bat, we've seen the ball when it gets fouled off of a player's body, and you could see the heat signature from a slide."

Much of the imaging technology for Hot Spot was developed for military applications, says Warren Brennan, managing director of BBG Sports, the Australian firm that developed Hot Spot. The demand from military organizations, Brennan says, has brought to the market infrared video cameras with frame rates high enough for television replay applications. Hot Spot operates at about 100 frames per second, which is faster than an ordinary on-field camera but slower than a super-slow-motion replay camera, Davies says.

Thermal imaging brings its own technological challenges, and Davies suspects that technology such as Hot Spot will probably only find use a few times per game. As an illustration, Brennan tells the story of a cricket match in which a spectator's actions inadvertently spoiled the infrared shot. "All of a sudden, in the background, a person walked past and it looked like a flashbulb went off," he says. "In the end we figured out that it was a guy smoking, and that changed the dynamics of the whole frame, because that was the hottest thing in the frame."

As imaging technology has progressed from what Brennan calls a "dark art," those kinds of flare-ups have become less of a pitfall. "Predominantly what we try to do is keep as much out of the shot as possible," Brennan says. "There are a couple companies now that make zoom lenses for infrared, so we've got more flexibility in framing that picture."

It remains to be seen if baseball's foray into the infrared will flame out or whether Hot Spot will join strike-zone monitors and football first-down markers as a regular part of the sports fan's viewing experience. "A lot of trying out new technology is seeing how it performs out in the wild," Davies says. "I think that every game we're learning what we're going to be able to see and what we won't."

Last night's disputed foul ball certainly showed that thermal imaging has some applications in baseball. "We might not get as good a shot as that for the rest of the matches," Brennan says. But, as with strike-zone monitors, what the television viewer sees does not always match up with the umpire's call, and it is the umpire's call that counts. Having lost game 1, vindication by Hot Spot will probably be cold comfort to Beltre and the Rangers.