Paolo Guerrero is out, and if that's an unfamiliar name, you're obviously not Peruvian.

Guerrero - of Bayern Munich, Hamburg and Corinthians fame - is Peru's all-time leading goalscorer with a record of 32 strikes in 86 appearances.

He's not past his prime, either, notching an equal-record five goals throughout qualifying to ensure the South Americans would be in attendance at their first World Cup since 1982.

Guerrero, however, will not be.

The 34-year-old tested positive for cocaine, as well as a banned metabolite (performance enhancing substance) after Peru's World Cup qualifier against Argentina last October.

The forward was originally banned from all FIFA competitions for a year, which would have kept him out of Russia had the ban not been reduced by FIFA, after an appeal, to six months.

The Court of Arbitration in Sport (CAS) overruled FIFA's sanction and imposed a 14-month ban.

CAS heard the case after an appeal from the World Anti-Doping Agency, which had originally requested a 22-month ban. It's unclear who was on the CAS panel that adjudicated Guerrero's case. 

CAS released a stament after the ruling, recognising that FIFA's six month ban didn't fit within its guidelines.

"The CAS Panel confirmed the existence of an ADRV [anti-doping rule violation] committed by Mr Guerrero, but also accepted that he did not attempt to enhance his performance by ingesting the prohibited substance," the CAS statement read.

"However, the panel considered that the player did bear some fault or negligence, even if it was not significant, and that he could have taken some measures to prevent him from committing the ADRV.

"Considering that, in case of no significant fault or negligence, the sanction should, in accordance with the applicable FIFA rules, be in the range of one to two years of suspension, the CAS Panel considered that the appropriate sanction would be 14 months in light of the Mr Guerrero's degree of fault."