* !Picby Pete Bodo*

Given the historically unpredictable nature of the men's singles event at the Olympics, it's borderline crazy to take informed guessses at how things will shake out.

After all, Roger Federer—the man most spectators and pundits would name the greatest player of all time—has never won any Olympic medal in singles (can you name the men he lost to in his four Olympic efforts?) For that matter, neither did the other Open-era contender for that honor, Pete Sampras.

Guesswork at the best of times, the grass surface on which this year's medals will be decided adds yet another volatile element to the mix. The matches are also best-of-three sets, which suggests we'll see plenty of upsets owing to how easily a player with a hot hand can run through two sets on turf, against an opponent of any quality.

Throw in the absence of defending gold medalist Rafael Nadal and you just know things are going to get a little western in this event. So instead of waiting for the draw, let's take a look at who's hot—and who's not—as we head into Olympics. I'm only going to comment on certain players who strike me as falling into one or the other category. Some, like Andy Murray, just seem like they could go either way. We'll take the men first.

No. 25 Milos Raonic. . . Hot!I'm sure Raonic wasn't ecstatic with his grass-court season; on the other hand, it was nothing less than solid. The highlight was Halle, where Raonic took Federer to a third-set tiebreaker before the pride of Thornhill, Ontario, capitulated in the quarters. There's no shame in losing to Sam Querrey at Wimbledon, although Raonic's subsequent failure against No. 112 Benjamin Becker at Newport must have been tough to swallow.

Never mind. Raonic's power game, built around his serve, is very effective at Wimbledon, and you have to love his Olympic spirit—as represented by his decision to stay on grass instead of picking up some easy cash and rankings points between Wimbledon and the Olympics on either hard or clay courts.

No. 23 Philipp Kohlschreiber. . . Not. Kohlschreiber bounced Nadal from Halle, and it took Jo-Wilfried Tsonga to keep him from advancing to the semifinals at Wimbledon. You'd think Germany's top-ranked player would have a great opportunity in these Games, but Kohlschreiber is actually playing this week in Kitzbuhel, Austria—even though he's the lone German representative in the men's draw.

Kohlschreiber will go straight from two red-clay tournaments into a grass event that will be well underway if he makes his No. 1 seed and lands in the Kitzbuhel final. I think that even violates the ATP's own rule against being entered in overlapping events.

The thinking behind this scheduling is, frankly, unfathomable. Can it be that the bragging rights to Germany—Florian Mayer, the next-highest-ranked German, is the No. 2 seed in Austria—and all that being No. 1 near home promises, endorsement and bonus-wise, is an issue here?

No. 22 Andy Roddick. . . Hot!** Anyone who's been to three Wimbledon finals and a semifinal, and was beaten in those matches by no less a player than Federer, is a threat to win on grass. While Atlanta, where Roddick won last week, is a hard-court tournament, emerging as the top American there surely boosted his morale. He'll return to Wimbledon, where he has had such a great if bittersweet history, ready to roll the die in best-of-three shootouts. Sure, he's struggled and fallen out of the Top 10 in which he was a fixture for a decade. But I still like his chances, not least because whatever else he is (or isn't), Roddick is a terrific competitor.

No. 15 Marin Cilic. . . Hot! Having boosted his ranking up into a solid seeding position, Cilic will go into the Olympics with plenty of momentum. He was ranked No. 25 at the start of Queen's Club, won that grass-court tune-up and lost in the fourth round of Wimbledon to finalist Murray—but not before he and Sam Querrey had played the second-longest match in tournament history (in elapsed time) in the third round. Cilic then went on to win on home soil in Umag, and did anyone else notice that in the semis of Hamburg, he played Tommy Haas tough in a tiebreaker, then folded his tents, dropping the second set, 0-6. Olympics on your mind much?

!PicNo. 9 Juan Martin del Potro. . . Not.That other kid from Tandil, Argentina, Juan Monaco, is breathing right down del Potro's neck, having cracked the Top 10 for the first time this week. That puts Delpo's problem into perspective. It took a fine effort for him to get back into Top 10-territory after he missed most of 2010, but let's face it—the 2009 U.S. Open champion seems to have stalled, and he appears to lack the requisite confidence and determination demanded by matches against the very top guys.

Del Potro may get over that and win more majors, but for now he seems to be spinning his wheels. Much like Tomas Berdych, though, a sudden change of attitude or rise in confidence and he could sweep all the other chess pieces off the grass-court board with a few mighty swings of that long right arm.

No. 7 Tomas Berdych. . .*Not*. It seemed for a good long period over the past two years that Berdych was on the ascent, and that a major title was almost sure to be the upshot. But the wheels began to fall off not long after he lost to Federer in the Madrid final on blue clay. His French Open was merely decent (loss to del Potro, fourth round), and he was a big disappointment on grass—he went out in his second match at Halle, and was the victim of a shocking first-round upset at Wimbledon (to Ernests Gulbis).

Look on the bright side; Berdych will be well rested for the Olympic games. And when you come right down to it, he's exactly the kind of big-game guy who can really do some damage in the Olympic format.

No. 5 David Ferrer. . . Hot!While accustomed to playing picador to Rafa's matador, Ferrer is having a career year at age 30, and you can bet that he's just dying to make just one gigantic career statement—like win a Grand Slam, or sneak away with Olympic gold—before he passes to the downhill side of career. These chaotic Games, where the best-of-three format is used, will boost his chances. Ferrer has five titles so far this year, and he demonstrated in his run to the quarterfinals of Wimbledon that he can play well enough to win on grass despite being more proficient on clay.

No. 2 Novak Djokovic. . . Not. Sure, he's the No. 2 player in the world and won a Grand Slam title to start the year, but he's won just one other title—and lost in three finals. Months ago, Djokovic declared that his big goals for this year were the French Open (that didn't work out) and the Olympic Games. That puts a little pressure on him in London, just as he's coming off a painful semifinal loss at Wimbledon to Federer. None of this means that Nole can't or won't run the table and bag gold, but given the choice between coming in with motivation or momentum, I'd take the latter any time.

No. 1 Roger Federer. . .Hot!!!!* With that out of the way, the answer to the above question is: Federer lost in the bronze-medal match of the Sydney Games in 2000 to Arnaud Di Pasquali -after* he lost to Tommy Haas, who bagged the silver medal (in the first two Olympic tennis events, the losing semifinalists both were awarded bronze medals. Starting in 1996, the losing semifinalists played a match for the bronze). In 2004 Federer lost to Tomas Berdych in three tough sets in the round-of-32 in Athens; and in Beijing in 2008 Federer lost to James Blake in the quarterfinals—Blake's lone win over Federer in 11 career matches.