“The tough part is that I’m starting from zero,” Viktor Troicki says as he wraps up a practice session in the sleepy alpine town of Gstaad, which plays host to this week’s Swiss Open, the scene of his comeback from a controversial 12-month doping ban. “I won’t have any protected ranking or anything so that’s going to be hard. But I’ve made it to the top once so I’m ready to do it again.”

Troicki pauses. His statement of intent is imbued with a quiet determination, stemming from the events of 2013 which he and many others still regard as a deep injustice.

Wind back 15 months to the 2013 Monte Carlo Masters. Troicki had just been comprehensively outplayed in the first round, but as a matter of procedure, he still needed to complete a blood test. It’s a routine process for most players, but Troicki has a deep-seated phobia of needles which makes every test a trauma. Feeling unwell, he requested it to be postponed to the following morning.

Troicki and his team say that the on-site doping control officer agreed, he took the test next day, and thought nothing more of it. As with every other test taken throughout his career, the results returned negative. But to his horror, two days later he received an email from the ITF informing him that he faced a potential two-year ban for allegedly refusing to take the test on time.

Three months later, he was banned from tennis for 18 months. An ITF tribunal panel refuted his claim that their official had told him he could postpone it. "Her response was that this was not a matter upon which she could advise the player," the panel said.

Looking back, Troicki is still in disbelief at how the trial proceeded. “It was amazing how the lawyers were going really hard for the maximum suspension,” he says. “I’m a tennis player and yet this was coming from the International Tennis Federation for whom I’ve played a lot of tournaments. That was really disappointing. I made my name through tennis and then they do this to me.”

He turned to the Court of Arbitration for Sport, but when the hearing took place in October, it came down to his word against the ITF. Lacking requisite evidence to overturn the ban altogether, it was merely reduced to 12 months.

“The funny thing is that the doctor who gave me the wrong instructions, she continued working,” he says. “She just continued doing her job and that’s because she doesn’t have rules. We players have rules and she just has instructions to follow. For me that’s kind of silly. She made a mistake and she hasn’t been sanctioned by anyone.”

Troicki’s feelings were shared by Novak Djokovic. The pair have known each other since Djokovic was eight years old, and at last year’s World Tour Finals he released an emotional statement in support of his friend.

“He gave me the most support out of all the players,” Troicki said. “He’s shown that he’s a great friend and even though he faced problems because he was supporting me, he still stood by me and tried to help as much as he could. He was one of the first guys to publicly support me and I will never forget that.”

Not everyone was on his side. Andy Murray hit out at Troicki and Marin Cilic, who was also banned for four months for accidentally ingesting a banned stimulant, accusing them of “unprofessionalism,” a move which infuriated Cilic’s coach, Goran Ivanisevic.

“The players have to be more like a family,” Ivanisevic said. “Troicki’s case is ridiculous. He’s now having to start from zero. From zero, for a crime he didn't commit. It’s a f***ing joke because it’s the official’s word against his and they believe her, not him. And the ATP doesn’t do anything even though they’re supposed to protect the players. If you cheat I’m for banning, but come on, for this? You can’t put everybody in the same basket. It’s not fair.”

In Troicki and Ivanisevic’s eyes, he is a victim of sporting politics. Sport has been wrestling with the dark spectre of doping for some time, but for many years, while an almost endless sequence of big-name positive tests brought baseball and cycling almost to their knees, tennis remained relatively immune.

But Lance Armstrong’s long-awaited confession last January cast a shadow which sent shivers through the entire sporting universe. Suddenly there were hints that tennis may too have something unpleasant lingering in the closet. Murray and Rafael Nadal expressed surprise that they hadn’t been tested more. Many players called for the ITF to introduce the same biological passport system being implemented in cycling.

Troicki believes the federation was simply waiting for an opportunity to ease the pressure, to show everyone they were taking doping seriously. “I feel they wanted to use me, to put me down for a long time to set an example,” he said. “My tests were always negative and they know that. I’ve always been against any kind of doping and use of illegal substances. I’ve done a lot of tests and I’ve never even thought about taking something illegal. Even this year while I’ve been banned they’ve tested me a lot of times.”

Now 28, Troicki is currently ranked No. 847 in the world. He faces a long slog through the backwaters of the game, playing the kind of events he thought he left behind a decade earlier.

There will be few wildcards to ease the journey back. Instead of heading to North America for the upcoming hard-court swing culminating in the U.S. Open, Troicki will spend his summer competing in a series of Challenger tournaments, amongst the journeymen and the hungry young upstarts, all keen to take the scalp of a player once ranked 12th in the world.

Even finding a place to launch his comeback was not easy. As a former semifinalist, Troicki initially hoped for a wildcard into this week’s ATP event in Umag, but he was overlooked in favor of three Croatian juniors before Gstaad eventually answered his plea.

The draw, pitting him against rising Austrian star Dominic Thiem, epitomized the struggles he will face to return to the top of the game. A year is a long time in sport and a new wave of talented youngsters are starting to emerge. Troicki knows he will have to be patient.

“I’m not expecting everything to happen straight away. There’s going to be a bit of pressure but I haven’t played any official tournaments for a year. I don’t know how good I’ll be against the top guys. I might need two matches or I might need three tournaments to get things started.”

There will undoubtedly be difficult times on the road ahead, but Troicki does not have to look far for motivation. He remembers last year’s Davis Cup, when he was banned from attending Serbia’s training camp during both their semifinal and final ties, and even from being present inside the stadium.

“It was kind of ridiculous what they were doing to me. I just wanted to watch it as a normal spectator but the Serbian federation told me that the ITF were really putting pressure on them. They didn’t want me in the stands, in the arena at all. They even wanted to put my photo on each door of the arena like a criminal to say that I was forbidden to be there.”

However, the ITF say they did not choose to deliberately ban Troicki from the Davis Cup ties.

"It was not an ITF decision not to allow Troicki to attend the final," they informed TENNIS.com. "The WADA code and therefore the Tennis Anti-Doping Programme rules do not allow any suspended player to attend any event covered by the program."*

The idea of practicing for months on end without a goal is a crippling prospect for any professional, but Troicki drew on the support of his coach and physio who stuck by him despite receiving multiple alternative offers.

“They felt really down in the beginning, they felt for me you know, and that’s why they want to continue working with me, get me back on the right track. My coach wants me to be even better than I was. That means a lot to me.”

Troicki brightens as he describes his team’s attempts to put a positive spin on his predicament. He feels it may actually aid his longevity as a player. Lasting 11 months of the year, the tennis circuit is relentless and most players admit they can ill-afford to take more than a week off from training. Even holidays are booked only in the knowledge that a tennis court is nearby. So after more than a decade as a professional, he was finally able to recharge.

“I took the chance to do all the things I hadn’t been able to do while I was playing tournaments,” he said. “I was skiing a lot in the winter. I was hanging out with my friends, just trying to forget about what happened to me. It was hard at first to begin working again, but I’ve been working really hard on my condition and as time went on I became more motivated and more pumped to come back. I realize what I’ve missed.”

But bitterness can also be a powerful motivation, and even as he talks through the benefits of relaxation, that lingering sense of injustice is never far from the surface.

“I will always feel that,” he says. “Of course. The ITF tried to destroy my career and I will never forget what happened. In the court they really went after me and they really wanted to put me down and ruin me completely. But I hope to show them they were unable to do that. I will be back.”

David Cox is a regular contributor to TENNIS.com.

*This quote and the preceding sentence was added on Tuesday, July 22.