TOKYO — After returning to the ATP Tour in style by beating Viktor Troicki 6-3, 6-4 at the Japan Open on Tuesday, Milos Raonic called for a review of the tennis circuit.

It was Raonic's first match following a seven-week absence after left-wrist surgery. The big-serving Canadian has withdrawn from five events this year, and conceded walkovers at two others.

"It's been very frustrating," said Raonic, who started the year at No. 3 and has slipped to No. 12 in the rankings. "I've had more than a dozen different injuries and reasons that have kept me away from tournaments. That hasn't been fun because I haven't been able to focus on tennis, I've been focusing on 'Can I play today or can't I?' rather than, 'What do I need to do with my tennis game?'"

Raonic knows tennis isn't a sport that's easy on the body, and the travel and length of the season are demanding, too.

"I believe out of those of us that finished top five last year, I'm the only guy still trying to play this year, and none of the top five played the U.S. Open," Raonic said. "Maybe it's testament to some kind of reform being needed for the sake of players' careers, and being able to provide a certain calibre of tennis for spectators.

"Scheduling, the length of the year and how spread out — geographically and throughout the year — the tournaments are, especially the top tournaments for the top players, is something that deserves a second look. It's hard to peak four times of the year for Grand Slams, let alone for other tournaments."

The 11-month season has long been an issue for players, something the men's and women's tours have taken some steps to address.

Even the biggest stars on the men's tour, Roger Federer and Rafael Nadal, had injury layoffs before returning to win two major titles each this season.

Raonic thinks a more compact season would help the competition across the board.

"Give the players that really stand out mandatory events, give them a chance to play everything within a seven-month period so they can really focus on themselves health-wise, but also on improving, because you need that time," Raonic said. "We're the only sport, outside of golf maybe, that plays as spread out as we do without any time for rest."

Raonic next plays Yuichi Sugita, who took the first set 6-4 from Benoit Paire when the Frenchman retired with fatigue.

Home-crowd favourite Taro Daniel was thumped by Yen-hsun Lu of Taiwan 6-1, 6-3 and gave his backing to Raonic's review call.

"It's ridiculous the way the tour's scheduled," Daniel said.

"You see how many people are injured right now. Half the top 10's out, 80 per cent of players have some sort of pain right now. There needs to be a bit more space between the tournaments; there are players doing crazy stuff like playing in the U.S. one week, China the next week, and after Roland Garros playing 15 weeks in a row.

"It's a great opportunity for us to play different places around the world, and it's really exciting, but it's a little too hard. It's easy for us to say it's too much but then how are we going to change it? I don't know what the solution is, but I feel something needs to change."

Daniel said he was splitting from his coach and moving from Spain back to Tokyo.

"I was playing really well until Roland Garros, then I had a bit of a physical letdown, fatigue — a lot of matches and heat during those weeks," he said. "My confidence isn't great right now. I had great practices this week, felt like I could do something good here, but I got killed out there today."

Lu next faces Richard Gasquet, who beat sixth-seeded Sam Querrey 6-4, 7-6 (2)

The Frenchman missed the opening five Masters events this year, following appendicitis surgery and subsequent back problems. Those back problems also forced him out of two other events.

"Now I'm feeling fit," Gasquet said. "I had appendicitis then everything went wrong with my body after that. The back problems came after that surgery, my recovery was very bad, and I started practicing a little bit too quickly, after five weeks — I wasn't ready. I didn't think it would be so tough to recover — of course I'm not 20 anymore, I'm 31."

Gasquet said the players outside the so-called Big Four need to play a lot of tournaments because they lose more often.

"We go to Australia, then we go on clay courts, we go on hard courts, need to change the type of balls, and you're jet-lagged," he said. "Tennis is very demanding — when I came on tour 15 years ago the 100-ranked player was not so difficult to beat, now they are very good so it's a big difference.

"Tennis is a tough sport. Of course there's a connection between the length of the tour and injuries, but it's a bit tough to say whether we should play more or less."