Why grass can be a slippery slope

— -- LONDON --   There will be a little extra trepidation for players as they step onto the courts on the third day of Wimbledon this week. A year ago, this was Wild Wednesday, a day when Roger Federer , Maria Sharapova and Victoria Azarenka followed Rafael Nadal out of the tournament, and seven players had to retire or withdraw from their matches.

A repeat is unlikely, but the first few days do seem to offer greater potential for upsets and injuries. The tournament has just begun, the courts are still green and unworn, and the players are only just getting their footing -- quite literally.

"This new, fresh grass, we're not quite used to it," said Federer. "As you go deeper in the tournament, it becomes more clay-courty, hard-courty, with a bit of grass on it. It's easier to move, the ball bounces a bit higher; it becomes more what we're used to."

This is the portion of the tournament reminiscent of the older days, before the grass became slower and higher-bouncing. The slippery surface and the bending required to get low-bouncing balls can be tough on the lower body, leading to injuries.

A year ago, a wet spring led to the grass being less-seasoned than usual, and players who suffered injuries from slipping included Azarenka (twisted knee), Sharapova (bruised hip) and Steve Darcis (damaged shoulder).

Even without such problems, players usually complain of aches in their legs as their muscles get used to the different movement required on grass after several weeks of playing on clay. There are only two weeks between the French Open and Wimbledon, and those who have gone deep into the French Open tend to be less prepared -- and frequently tired from their efforts across the Channel.

"A lot of people underestimate the physicality of the grass itself, the way it's changed in five, six years -- how physical it's become," said Sharapova, who has reached the French Open final for three straight years and won two titles. "So that adjustment is always a bit tricky in the beginning on the body."

On a surface where matches often turn on one or two points, there is little room for even top players to play their way into shape. So put an underprepared big name against a tough opponent during the first week, and an upset isn't out of the question.

"This can easily happen here," said Novak Djokovic. "Grass is a very rare surface in our sport."

Djokovic, who reached the French Open final, did not play any grass-court events before Wimbledon. "It's very tricky for top players. Still you don't feel very comfortable. The players you are playing against who are lower ranked, they have played a tournament or two coming in. So they have more matches [on grass]," he said.

"So especially for the top players, for us who haven't played a lead-up event, who don't have a few official matches, it's going to take some time to get into match play on this surface."

Djokovic sees the usual suspects being challenged this year, as well, especially by some of the younger players starting to gather in the top 10. "There is a new wave of players, especially the younger generation, like [Grigor] Dimitrov, and [Milos] Raonic and [Kei] Nishikori, [Bernard] Tomic, those kind of players, that have proven that they can win against the top guys in the big events,'' Djokovic said.

There are also players who pose a particular challenge on grass, like serve-and-volleyers or big servers. "If you have a big serve like [Ivo] Karlovic, [John] Isner, somebody coming the opposite way, you have to be ready to play tiebreaks," Djokovic said.

Although most players stay on the baseline these days, the newer grass at the beginning of the tournament still rewards classic net play, especially since opponents are unused to playing against this type of game. Federer and Nadal went out on back-to-back days a year ago to Sergiy Stakhovsky and Steve Darcis, both of whom regularly came to the net and took the match away from the two greats. Dustin Brown, who beat Nadal in the Spaniard's opening match at Halle, also plays an attacking game, with Nadal saying he was hardly able to touch the ball.

For the world No. 1, this Grand Slam tournament is the one he feels least confident in.

"I arrive to Roland Garros, I already played for one month on clay," Nadal said. "I played a lot of matches. So more or less, I can imagine how I'm going to play. US Open, is the same. Australia, is true that is the beginning of the season, but is surface that we know, so is not a dramatic change. Here, yes. Especially at the beginning of the tournament, the courts are a little bit faster."

The draw has also sent some intriguing opponents Nadal's way, including a potential second-round clash against either Lukas Rosol, who defeated Nadal in the second round in 2012, or Benoit Paire, a wildly unpredictable player. At least neither Federer nor Sharapova is playing on Wednesday this year, though Federer could get a challenging second-round contest against either Julien Benneteau or Gilles Muller. Sharapova and Serena Williams are not only in the same quarter, but also have a lot of other tough players grouped with them.

So even for the title contenders, getting through the first few rounds is just as important as their more high-profile matches in the second week. Just ask Nadal: Since his first appearance at the tournament, he has either reached the final, won the title -- or was sent home by the second round.

"Once you win a few matches," he said, "everything becomes more logical."

Until then, however, a few more wild results could be in store.