SHANGHAI, China — Martina Hingis, one of the game’s greatest players, tests positive for cocaine and retires. Nikolay Davydenko, a top-5 player under investigation for suspicious gambling on one of his matches, receives a fine for lack of effort; a week later, a chair umpire mocks Davydenko for double-faulting too often and questions his commitment. Numerous players announce that they have received offers to throw matches. An Italian journeyman, Alessio Di Mauro, receives a 9-month suspension for placing 120 bets on his professional colleagues. Another top player, Tommy Haas, suspects that he was poisoned during a Davis Cup match against Russia. Investigators uncover a murder-for-hire plot at the Australian Open.

Okay, I invented the last one, but would you be surprised these days? For all the gripes fans might have had about tennis less than six months ago — low television ratings, too many players who skip important tournaments, a season that’s two months too long — they had few doubts that the game was among the cleanest in the world. Now, as the season that can’t end soon enough mercifully draws to a close, fans can’t help but ask: What’s next? Will Roger Federer retire? (Not until 35, he said this weekend, and thank goodness.) With any luck, all we’ll have at the Tennis Masters Cup in Shanghai this week is a little tennis. Here’s a rundown of what to expect from the top eight men in the world.

RED GROUP (Roger Federer, Nikolay Davydenko, Andy Roddick, and Fernando Gonzalez): It’s a measure of Federer’s greatness that some consider 2008 an offyear. The fact is, he has turned in another spectacular performance, no matter how you look at it. Yes, he twice lost back-to-back matches to the same player (Guillermo Canas and David Nalbandian), but those losses didn’t amount to much. For the second straight year, he reached the final of all four majors and won three of them. He won’t win double-digit titles this year, and you can consider that as a sign of things to come. Federer will celebrate his 27th birthday next year, prime for a tennis player. No doubt he has many years, and probably many majors, left in him. But he’ll play fewer events, and win fewer of them, from here on out. Still, to string together two years like his last two is remarkable. Forget the debate about whether Federer is the athlete of the year — that one is obvious. What’s more interesting is whether he’ll become known as the best athlete of the century.

Last year, Federer capped his year with an undefeated run at the Masters Cup. Here’s saying he’ll do it again. He’s owned the three players in his group: Andy Roddick (14–1 against the American), Nikolay Davydenko (10–0), and Fernando Gonzalez (10–0). He’s also fairly well rested and perhaps a little hungrier than usual after two tough losses to Nalbandian. His opponents, meanwhile, are either playing poorly (Davydenko and Gonzalez), or recovering from injury and preparing for bigger things (Roddick has his eyes on the Davis Cup final against Russia).

Roddick ought to at least qualify for the semifinals if he doesn’t decide to pull out sooner to rest his sore heel and knee. Davis Cup is Roddick’s priority at the moment, so he shouldn’t suffer from nerves or tension this week. Last year, he came within a point of beating Federer. If Roddick is serving well, he might push Federer again. And Gonzalez and Davydenko won’t stand a chance against his serve on a fast indoor court. If Roddick plays Federer twice — once in round-robin play and again in the final — he should be more than prepared for Russia.

If there’s a wild-card in this group, it’s Gonzalez. The Chilean played wonderfully in Australia, where he limited his errors and multiplied his winners for a spot in his first Grand Slam final. But the rest of the year has been a downer. Look for Gonzalez to try to regain the form that he found earlier in January.

As for Davydenko, who could blame him if he just decided to skip town as quickly as possible? ATP investigators have questioned his brother and wife as part of their gambling probe, and Davydenko’s every move has become the subject of analysis for newspapers, commentators, and the tour. In less than a year, Davydenko has gone from anonymous to hated, and he’s not coping well with his newfound role. Expect him to lose early.

GOLD GROUP (Rafael Nadal, Novak Djokovic, David Ferrer, and Richard Gasquet): While all four players in the Red Group have qualified for the Masters Cup before, three rookies — Novak Djokovic, David Ferrer, and Richard Gasquet — join the world’s no. 2, Nadal, in the Gold Group.

Nadal has played better recently and should qualify for the semifinals, especially now that he defeated Gasquet yesterday, 3–6, 6–3, 6–4. It’s less clear what we’ll get from Djokovic. He’s had a superb season, appearing in two major semifinals and his first major final. He’s also worn out. Since the U.S. Open, Djokovic has played Davis Cup, a tournament in Vienna, and the two Masters events in Madrid and Paris. He won only five games against Fabrice Santoro in Paris, after having his wisdom teeth (and seemingly his legs) removed. Yesterday, he lost his first match of the tournament to Ferrer, 6–4, 6–4. Djokovic has now played 85 matches this season, the same number he had played in his young career before this year. More than anyone else in the field, he needs a rest, and it might come soon.

ALTERNATES: The top-8 are a banged up bunch this year, so don’t be surprised to see one or both of the alternates, Tommy Robredo and Juan Ignacio Chela, get in on the action. The shame here is that Nalbandian, the hottest player on the tour right now, is not among them. He decided not to travel on the off-chance that he would play. His presence would make this tournament much stronger. Robredo didn’t impress here last year. Chela, meanwhile, has put together a fine season: 40–25, one title, and quarterfinal showings at the U.S. Open, Miami, and Indian Wells. His indoor results this year, though, haven’t been great. Chela lost his last three matches (Madrid, Basel, and Paris) without winning a set. If Robredo and Chela remain on the sidelines, the tournament will not suffer.

Mr. Perrotta is a senior editor at Tennis Magazine. He can be reached at tperrotta@nysun.com.