If comparisons with other players who have been banned for drugs offences are anything to go by, Maria Sharapova could return stronger than ever in the wake of her 15-month suspension.

Sharapova makes her controversial comeback here at the Porsche Tennis Grand Prix, having been allowed to play despite her ban expiring only at midnight on Tuesday. The tournament started on Monday, but organisers have scheduled her first match, against Italy’s Roberta Vinci, for Wednesday.

Viktor Troicki and Marin Cilic returned to competition in recent years after serving 12-month and four-month bans respectively. Both agree that they came back stronger, physically as well as mentally.

Maria Sharapova's comeback divides opinion Show all 17 1 /17 Maria Sharapova's comeback divides opinion Maria Sharapova's comeback divides opinion The Maria Sharapova wildcard debate A number of current and former tennis pros have weighed in with their opinion on whether or not Sharapova should be handed a series of wildcards as she returns from her suspension for taking the cardiac drug meldonium. AFP/Getty Maria Sharapova's comeback divides opinion Eugenie Bouchard She’s a cheater and to me, I don’t think a cheater in any sport should be allowed to play that sport again.. I think from the WTA it sends the wrong message to young kids: ‘Cheat and we’ll welcome you back with open arms’. Getty Maria Sharapova's comeback divides opinion Caroline Wozniacki "First of all I think she's a good draw for tennis, women's tennis in general. But two, I think it's questionable allowing - no matter who it is - a player that is still banned to play a tournament that week. So from the tournament side I think it's disrespectful to the other players and the WTA. Obviously rules are twisted and turned in favour of who wants to do what." Getty Maria Sharapova's comeback divides opinion Victoria Azarenka "She has such a huge fanbase and obviously that's going to bring more attraction to see how she will do, so I think it's good for tennis, good entertainment." Getty Maria Sharapova's comeback divides opinion Dominika Cibulkova “I don’t think it is right but what can we do about it? She’s still banned but she can come on site on Wednesday, that’s pretty strange." Getty Maria Sharapova's comeback divides opinion Angelique Kerber "It's a little bit strange for the players that she can walk on site on Wednesday and she can play on Wednesday." Getty Maria Sharapova's comeback divides opinion Heather Watson “From the tournament standpoint, she will bring in the crowds and make money. But, from a moral standpoint, you should have to work your way back up if you've been on a ban. It just seems a bit easy.” Getty Maria Sharapova's comeback divides opinion Simona Halep "Her return is good for tennis, she is impatient, she wants to play and win." Getty Maria Sharapova's comeback divides opinion Venus Williams "I think the bodies have made their decision, and she has an opportunity to come back and continue her career. I think she should be allowed to continue that. If people want to give her wildcards, I guess that's the tournaments' decision as they weigh other wildcards. It will be nice to have her back in the game." Getty Maria Sharapova's comeback divides opinion Svetlana Kuznetsova "I understand, because if we talk about cheaters, people who cheat, you would say, 'Why would cheaters get a wildcard?'. But then if there is some mistake, you know, it's a little bit of a different story." Getty Maria Sharapova's comeback divides opinion Andy Murray "I think you should really have to work your way back." Getty Maria Sharapova's comeback divides opinion Roger Federer "It´s a tough one. What do you want me to tell you? Like you said, because it´s the first, it kind of is what it is. You know, some people will like it; some people won´t. She paid the price for what she did, so that´s all you can say there." Getty Maria Sharapova's comeback divides opinion Jo-Wilfried Tsonga "It's like if you give a sweet to a kid who did a bad thing, it's going to do it again. It sends the wrong message." Getty Maria Sharapova's comeback divides opinion Andy Roddick "If there's a smaller event that will benefit from having Maria, I don't begrudge them giving her the card. The Grand Slams are different. They're held to a higher standard because there's so much interest in them." Getty Maria Sharapova's comeback divides opinion Nick Kyrgios "I'm anti-anything that's performance-enhancing, massively against it. I'm not the one to say what [violators] should -- or shouldn't -- get afterwards, but it doesn't make sense to support people who cheat." Getty Maria Sharapova's comeback divides opinion Jack Sock I don't know. It's a tournament director's decision who gets [wild cards]. As a player, I have no say one way or another." Getty Maria Sharapova's comeback divides opinion And as for Maria herself? “I can’t control what people say. To have nicer things to say about me in press conferences, what will that change to my tennis?" Getty

Troicki won two of his three career titles after his suspension, which was imposed by the International Tennis Federation in 2013 after he failed to provide a blood sample for a drugs test. Troicki maintained that the doctor conducting the test gave him permission to delay giving the blood. His initial 18-month ban was reduced on appeal by the Court of Arbitration for Sport.

“I think it gave me more desire to come back stronger and it helped me in a way,” Troicki said. “Physically I was never better. I worked so hard, I had so much time to prepare. I just felt I needed to do more. I thought: ‘Maybe it’s not enough, let’s do more, run more, do extra gym, train more on the court.’ I think the work paid off. I think I was never in better shape.”

He added: “It’s hard to miss the thing you love. I grew up playing this game. I've been playing since I was a kid and I always dreamed of becoming a professional tennis player. I loved it so much. Once you stop playing and you don’t have it any more, then you feel how much you miss it.”

Troicki failed to provide a blood sample during the 2013 Monte Carlo Masters (Getty)

Cilic won the US Open in 2014, a year after he was suspended for nine months by the ITF after inadvertently ingesting a banned stimulant when taking glucose tablets. His ban was reduced to four months following an appeal to CAS.

The current world No 8 continued to work hard during his suspension. “I love to practise,” Cilic said. “That made me stronger. Maybe in the first few weeks I didn’t play tennis but I was doing the physical work. If I had been cleared to play after just one or two months I would have been ready within a week to play tournaments.

“I think mentally it made me stronger. I learned a life lesson. I realised how much I loved tennis and how much I missed it. Then when I was back playing I was like a little kid. I wanted to play all day.”

Cilic returned from his ban and won the US Open (Getty)

Sharapova has done plenty outside of tennis during her ban – including enrolling on courses at Harvard Business School and doing an internship at a London advertising agency - but in recent weeks the 30-year-old Russian has been working hard on her fitness and her game.

Max Eisenbud, her agent, told CNN earlier this month that she had been struggling with injuries at the start of last year but was now fully fit. He said she was so motivated that she wanted to extend her career at least until the 2020 Olympics.

Sharapova was initially banned for two years by the ITF after testing positive for meldonium at last year’s Australian Open. CAS cut the suspension to 15 months, ruling that the Russian had not been an “intentional doper”. Sharapova was unaware that meldonium - which she said she had been taking as a prescribed drug for 10 years because of a number of medical conditions including a family history of diabetes - had been added to the banned list of substances.

Sharapova will make her return at the Porsche Grand Prix (Getty)

Cilic, having fought his own battles with the ITF, has sympathy with Sharapova. “The ITF should be the ones protecting the players, teaching them and maybe having even more lectures for the players and the tournaments and making the players much more aware,” he said. “People do make mistakes. Then [the ITF say]: ‘We’re going to try to do everything in our power to sack you the worst we can.’ Coming from the ‘house’ organisation of tennis, it’s not nice.”

Troicki has similar feelings. “I was extremely frustrated and extremely disappointed with the system and with how the ITF do things, which is completely unfair,” he said. “There are people there who should have been sacked and who shouldn’t do the job that they do. But at the end of the day you can’t do anything about it.”

Sharapova has been given wild cards here and at the upcoming tournaments in Madrid and Rome. As she no longer has a world ranking because of her suspension, that was the only way she could play in such high-profile events.

Sharapova admitted to taking meldonium since 2006 (Getty)

Vinci is one of a notable group of players who do not believe Sharapova should have been given wild cards. “There are probably a lot of players who agree with me,” she said.

However, Cilic thinks the wild cards are justified. “She has done her suspension,” he said. “She did 15 months, which is a long time without playing tennis, especially with her own status, with what she achieved in her career. I think in every sense it’s right that she is able to get those [wild cards].”

Sharapova arrived here at the end of last week and has been practising at a club in the city suburbs. Players serving suspensions for drugs offences are not allowed on tournament premises.

Djokovic went out of his way to help his compatriot and friend (Getty)

Troicki, currently the world No 39, was in the same situation but was especially grateful to Novak Djokovic, who went out of his way to help his fellow Serb. Djokovic practised with Troicki both before tournaments and at off-site venues during them.

Although Troicki was given a wild card at his first comeback tournament in Gstaad, where he beat Dominic Thiem and reached the quarter-finals, for the most part he had to fight his way back up the rankings the hard way.

“It was a big help having that wild card,” he said. “I started believing in myself from the next tournament. I was playing smaller tournaments, Challengers, getting my ranking up. That good start gave me wings to start playing, to start to believe and play even better. I guess it was lucky at the start. Who knows if I had started badly?”

Sharapova, meanwhile, having always protested her innocence, might be fired by the same sense of injustice that drove Troicki. “I stayed strong, positive and I think those bad things made me better and stronger in my head,” he said.