Maria Sharapova, a five-time Grand Slam winner, will make her comeback to the tennis tour this week at the Porsche Grand Prix.

After a long, controversial suspension, the Russian will face Italian and 2015 US Open runner-up Roberta Vinci on Wednesday in the first round in Stuttgart. From there, Sharapova could play Agnieszka Radwanska and Dominika Cibulkova in the second and third rounds, respectively. From there, Sharapova's draw would get even trickier.

Now that Sharapova's ban is almost over, here's what we know about her status now and questions we hope to find answers to in the coming weeks:

1. Why is Sharapova eligible to play Stuttgart?

Sharapova announced last March that she tested positive at the 2016 Australian Open for meldonium, a drug that can help athletes increase their exercise capacity. She was initially suspended for two years by the International Tennis Federation, but she appealed to the Court of Arbitration for Sport (CAS), which reduced Sharapova's suspension to 15 months last October.

Maria Sharapova will play a tennis match for the first time in 15 months, but there are still pressing questions about her immediate future. AP Photo/Damian Dovarganes

Sharapova has always maintained that she had been taking meldonium since 2006 because of a family history of heart disease and diabetes, and that she and her agent erred by failing to read an email informing them the drug had been moved to the banned list as of Jan. 1 last season by the World Anti-Doping Agency (WADA).

Sharapova chose Stuttgart for her WTA return because she was given a wild card into the event, which starts Monday and is sponsored by one of her sponsors, Porsche. Since the Russian-born champion cannot even step on site until her ban officially expires, her opener is among the few first-round matches that will be played Wednesday.

2. Will Sharapova have a ranking?

No. Sharapova fell out of the WTA rankings in October because she did not play enough in 2016 to compile any rankings points after the Australian Open. But with the European clay-court season about to begin, she already has three confirmed wild-card entries, into Stuttgart, Madrid and Rome, and could start amassing points again soon. Sharapova's game translates well to clay, as evidenced by her two French Open titles.

3. If Sharapova's suspension is over, why isn't she guaranteed to play the French Open or Wimbledon?

Tennis players who are suspended for doping cannot petition to have their rankings protected like players can if they are injured or take maternity leave.

That means Sharapova, who was ranked No. 4 in the world when she was suspended, has only two avenues right now to get into the main draw of WTA tournaments: She can play her way in through qualifiers and eventually raise her ranking enough to earn automatic entry into events again -- an unappealing chore for a five-time Grand Slam champion who just turned 30. The second option is that Sharapova could receive one of the wild-card slots that every tournament, including the majors, hands out.

So far, officials for the French Open and Wimbledon, tournaments Sharapova has won, have declined to say if they will give Sharapova a wild card because of the circumstances surrounding her case -- and their desire to project a tough stand against doping.

4. What do other players think about Sharapova's return?

Players and tournament officials are divided. Samantha Stosur has predicted Sharapova will get a cold reception in the women's locker room, and Andy Murray, Angelique Kerber and Jo-Wilfried Tsonga are among those who have said they don't believe any player suspended for drug use should get wild cards. Murray, in particular, believes the slog of having to earn your way back via qualifiers is a deterrent for players tempted to use performance-enhancing drugs.

Venus Williams has been gracious about Sharapova's return, saying she's served her time and the tour has missed her. Martina Navratilova and WTA chief executive Steve Simon have said similar things. Simona Halep has hinted she doesn't get what the uproar is about: "Sharapova] can receive wild cards because she was [once] No. 1 in the world; she's a Grand Slam champion. But I think even if she doesn't get wild cards, she can come back easy."

Sharapova knows her support within tennis has been eroded by two things: She has never interacted much with other players and admittedly has few close friends on tour. Additionally, her argument that she made a simple mistake while using meldonium sounds hollow to some, given the widespread use of the drug by Russian athletes amid allegations the country was running a state-sponsored, systematic doping program. As a result, scores of Russian athletes were banned from the Rio Summer Olympics and Paralympic Games.

Sharapova has long lived in the U.S., but she was born in Siberia and has always competed for Russia. She had hoped to do so again in Rio.

5. What has the ITF done since Sharapova's suspension to change or strengthen the sport's drug-testing policies?

ITF president David Haggerty -- noting how tennis has been hit by match-fixing allegations even before Sharapova's case came along -- has said he is committed to increasing transparency and nurturing public confidence in the sport.

The ITF decided in August that it will now announce when a player is serving a provisional suspension. The hope is to counteract past suspicions that some stars receive preferential treatment, and that some players who tested positive in the past served "silent bans" and even invented phantom injuries to explain their inactivity while they secretly waited for their doping cases to be heard.

Over the years, a fundamental tenet of sports drug-testing programs is the idea that athletes are ultimately responsible for whatever substances enter their body. But the CAS ruled in Sharapova's case that anti-doping organizations must nonetheless take reasonable steps to inform athletes of changes to the banned substances list and give them particulars.

Both the ITF and WADA said they will comply with that ruling.

Critics have also pushed the ITF to address why so many of the suspensions it has handed out in recent years have been reduced or dismissed on appeal by the CAS. Can the federation do a better job of building cases and tightening its controls and procedures?

One thing the ITF doesn't plan to do in the near future is release players' drug-testing histories. That's something Rafael Nadal asked for on his behalf after he decided to sue a former French minister, Roselyne Bachelot, for defamation in France. Bachelot charged that one of Nadal's many long layoffs from tennis was linked to a positive test, not injury. Both Nadal and the ITF rejected her claim.