The cover of the March issue of Ocean Drive, South Florida's coffee table glam-rock magazine, has Maria Sharapova clad in black leather perched upon a Harley-Davidson. It is a jaw-dropping image. A pity, then, that just as the ignition is about to be turned on a Masters Series tournament here that has become the epitome of sport and showbiz, her engine has spluttered to a halt.

When the leading players of women's tennis gathered on the Sony Ericsson Open's purple welcome mat yesterday, the blonde who has just become the sponsor's signature client was a long way back in their slipstream, although she had flown from California to show off her injured right shoulder in public.

The effects of the injury were enough to persuade the Russian that putting herself through the rigours of this particular tennis extravaganza would work against her season - a motive that may be deemed as self-serving but which underscored her importance to the health and vitality of the tour in general. How can they solve the problem of a tournament without Maria?

Her absence hurts twice as much, because Sharapova has just signed a three-year deal to become the umbrella sponsor's global brand ambassador. This is the event at which all their impressionist ideas come together and she cannot recall the last time she walked into a tennis venue without a racket bag slung across her (increasingly tender) serving shoulder.

Perhaps an explanation lies in the fact that Sharapova has been putting her body through too much stress. Since Boxing Day, she has clocked up a staggering 50,000-plus air miles, departing from Los Angeles via Singapore to Hong Kong for her chosen warm-up for the Australian Open; on to Melbourne, where she won the grand-slam title in circumstances that stretched her to the limit; to Tel Aviv for a tumultuous first Fed Cup appearance against Israel; back to Los Angeles for a stopover before flying to Doha (where she ran a fever but won the title); on to Dubai, where she had to withdraw, before returning to LA and getting behind the wheel to drive to Indian Wells, where she played in pain in the later part of last week and lost, feebly, in the semi-finals.

Hence, she flew to Miami on Monday with a sick note.

That kind of schedule is enough to drain anyone, whether cosseted in first-class or not. It also goes to the heart of why, in 2009, the Sony Ericsson WTA Tour is pressing ahead with a redesign of its calendar that will give the players a nine-week rest period in which, the tour hopes, they will not attempt to play in all the dash-for-cash exhibition events and undo all the good to their bodies that will have been done by reducing their commitments to the schedule proper.

The theory is that Sharapova will appear in tip-top shape in more tournaments. As she said yesterday: “Tennis is always going to be a priority until the day I lose interest in waking up and heading for where my rackets are stored - which right now I don't have with me.

“This feels so awkward. As long as that competitive flame burns bright - and I am a competitor, you know that - I feel I can be better as a player. I know how I want to play, how I can play, how much better I can be, and achieve all those things I still want to achieve. I set many goals for myself and my goal is to reach them all.”

The next of them - in a year in which the Olympic Games place an extra burden on those marquee players consistently asked to name their priority - is the French Open in May. As with Roger Federer, Sharapova needs Roland Garros to complete her grand-slam tournament set, although, as the 20-year-old (she gets the key to the door next month) said without irony: “There's really no added pressure because it's the slam I haven't won. It's not like I'm 26 and this is my last chance to win it, you know.”

Sharapova began the year in startling style at the Australian Open. She did not forfeit a set, although it was a tournament that was far removed from the norm of the leading women players not having to get themselves fired up until the quarter-finals.

Sharapova faced Lindsay Davenport, a former world No 1 and multiple grand-slam champion, in the second round, Elena Dementieva, a grand-slam finalist, in the fourth and Justine Henin, the world No 1, in the last eight. She overcame them all, but it took a lot out of her.

From there she embarked on a long-awaited Fed Cup debut for Russia in Israel, for which she could never have been properly prepared. “It wasn't so good the first few days because we arrived to a hurricane, so I was literally in my hotel room, watching movies non-stop - thank God, in English,” she said. “We had a couple of team dinners, practised for two days, then played in front of thousands of screaming fans. None of the girls had seen a crowd like that and it was funny because after my match, when we were all in the player lounge, they were like, 'Welcome to Fed Cup, Maria.' It was crazy.”

Sharapova has to deal with craziness all the time; it comes with the territory. “But basically this year I have not had a breather,” she said. “It makes it harder for me. I want to be out here playing - to see a draw without my name in it, it feels bad. I don't like doing press conferences announcing my withdrawal.

“But there are sacrifices you have to make and if I go out on court and am not 100 per cent, I could really hurt myself more because I'd get lazy, I'd be tired and if my mind isn't there, it's just not worth it.

“The scheduling this year is going to be the most difficult I've had. Right now, the next big thing is the French, but for me, it's just about getting on the practice court and making sure everything is right.”

Some of the free time she has will be spent in design-mode, for later this year there will be the launch of Sony Ericsson's “Maria Sharapova Phone”. And she has been involved in the creation from the word go. “If there's one thing I cannot live without, it's my mobile phone,” she said. “I have a notepad by the side of the bed and I'm always writing down the things I want on my phone. It's a real fun process.”

In May, Sharapova flies to Sweden to meet the company's product design team and help them to decide on the size of the buttons, the colours, the accessories, the graphics. You name it, Maria is in it.

The perfect image? That of Sharapova calling her mother from Centre Court next year, having won the Wimbledon title again. So long as you can pick up a signal under the roof.