(Reuters) - Buffalo Sabres forward Zenon Konopka has been suspended 20 games after testing positive for a banned substance, the National Hockey League said on Thursday.
Konopka, whose contract with the Sabres expires with the conclusion of the 2013-14 NHL season, said his positive test was the result of taking an over-the-counter product that violated the league's performance enhancing substances program.
"Unfortunately, I did not take the necessary care to ensure that the product did not contain a prohibited substance," Konopka said in a statement released by the NHL Players' Association.
"I want to stress, however, that I did not take this substance for the purpose of enhancing my athletic performance."
The NHL said the term of Konopka's suspension will be served at the beginning of any new contract.
Konopka had three points in 59 games last season, which he started with the Minnesota Wild before being claimed off waivers by Buffalo in January.
(Reporting by Frank Pingue in Toronto; Editing by Mark Lamport-Stokes)