Roman Kreuziger (Tinkoff-Saxo) will kick off his 2015 season Tuesday in the Tour of Oman despite having a biological passport case soon at the Court of Arbitration for Sport (CAS).

The six-day Tour of Oman’s lineup includes several of cycling’s top stars, notably reigning Tour de France winner Vincenzo Nibali (Astana), and sets cyclists up for the remainder of the racing season. Next month, the top WorldTour races continue with Paris-Nice and Tirreno-Adriatico.

Kreuziger’s schedule beyond Oman has not yet been announced, however. Much of his season, and career as well, will rest on the result of his biological passport case.

The CAS told VeloNews last month it has not yet scheduled a hearing date, which frees up the 28-year-old Czech’s opportunities to race for now. Although the Swiss court could clear him, if it rules the other way he could face a two to four year ban for doping.

The case arose from abnormal passport readings, reported last year by the UCI before the Tour de France. The UCI noted abnormal readings in samples from 2011 and 2012, when Kreuziger raced with Astana.

Tinkoff’s managers allowed him to race anyway in the Tour of Poland, but the UCI stepped in with a provisional suspension, which held until the Czech Olympic Committee cleared him on September 22.

Kreuziger returned to participate in a series of one-day races last October, and arrived this weekend to begin his season in Oman with the biological passport case still hanging over his head.

The UCI with the World Anti-Doping Agency (WADA) made an appeal to the Czech Republics’s decision October 23 to the high court. The court has yet to set a date, but judging on its prior passport rulings, it does not look good for Kreuziger.

When Italy cleared Franco Pellizotti, the UCI appealed to the court and won. Italian Pietro Caucchioli appealed his case to the Swiss court after being banned and lost.

Other cyclists, such as Leif Hoste and Jonathan Tiernan-Locke, are serving bans stemming from their passport.

The biological passport, introduced to cycling in 2008, is attributed with helping clean up the sport. It tracks blood and urine values throughout a cyclists’ career in order to build a profile. Consistent readings are fine, but abnormal readings could indicate doping.

Kreuziger’s main argument is that the UCI’s medics mishandled his samples and that he suffered from an under-active thyroid gland that could have altered the readings.

In January, he announced he had passed a polygraph test which he says proves he did not dope, use EPO, or receive blood transfusions. “I don’t have anything to hide and I am doing everything in my power to clear my name,” he said.