Maria Sharapova's failed drugs test could cost her up to £100 million

Maria Sharapova has been the highest-paid woman in tennis for more than a decade, and is worth an estimated £137 million. But her days of earning mega-millions may be at an end. This week she admitted to having taken a banned substance, and as a result, some of her most lucrative sponsorship deals are under pressure, which could end up costing her as much as £100 million in lost earnings.

Sharapova has been taking a medicine called meldonium for the past ten years - after being prescribed it by for magnesium deficiency, irregular heart test results, and a family history of diabetes. However, she continued to take it after it was banned in January, and tested positive for it in a drugs test. She says that she and her coaching staff didn't see any of the emails stating that it was banned. However, she has said she should not have missed it, and takes full responsibility for it.

Sponsors

As a result, her biggest sponsorship deals are under pressure. Nike said it had put her sponsorship on hold - it was due to run until 2018. Porsche had signed a deal for the rest of this year, but says it has postponed planned events with the player, and TAG said it had been discussing extending her contract but that after the news, it wouldn't be renewing her contract. Between them, these are thought to be worth around £10 million a year.

It's not known whether any other sponsors will take a similar approach, but they are worth an estimated £6 million a year between them.

Uncertainty

At the moment, none of her ongoing sponsors have declared they are dropping her for good. It's not known whether she will be banned from playing - and if so how long for - so they are not ready to make a final decision.

A worst case scenario for Sharapova could mean a four year playing ban, and even the end of her tennis career, as she is 28. Given that Forbes estimates she made just under £21 million last year - assuming she would otherwise have played to the age of 33 and continued making money at the same rate - the Daily Mail's estimate of a loss of £100 million of sponsorship is possible.

However, there is plenty of legal to-ing and fro-ing before we know the outcome for Sharapova. It's thought she could face a ban, but there is speculation as to whether it could be for as little as a year or as long as four years.

A separate possibility is that her legal team could apply retrospectively for an exemption on the grounds she was taking the medicine for health reasons, in which case she would be exonerated. There's plenty of water left to flow under the bridge before it's known whether Sharapova will lose any of her ongoing sponsorship deals at all - let alone £100 million worth of them

Dropped

One sports sponsorship agency told Reuters that sponsors now tended to have a 'zero tolerance' approach, because the companies themselves are under such scrutiny.

Just two weeks ago Nike was quick to drop boxer Manny Pacquiao after homophobic comments, while back in February, Nestle dropped its sponsorship of a children's athletics programme for the IAAF because of the ongoing doping scandal.