Byrd's positive test was triggered by Ipamorelin, a growth hormone releasing peptide, according to a statement from Major League Baseball. The suspension is without pay, and Byrd will forfeit what remains of his $1 million salary for the 2016 season.
It's the second such violation for the 38-year-old slugger, who served a 50-game ban in 2012 after testing positive for the drug Tamoxifen. Since that suspension, Byrd's earned nearly half of the $38 million in salary he's amassed during his 15-year career. The league increased its penalty for a second drug violation in 2014 from 100 games to a full season.
In a statement obtained by Ken Rosenthal of FOX Sports, Byrd said he and his lawyers believe he tested positive for Ipamorelin due to a tainted supplement. However, Byrd acknowledged that some of the supplements he was taking were not on the NSF Certified for Sport List, and because of that, he assumed certain risks in using them.
"I alone am responsible for what I put in my body, and therefore, I have decided for forgo my right to an appeal in this matter and accept the suspension," he said.
Byrd, who signed with Cleveland as a free agent this spring, has come under fire in the past for working with controversial figure Victor Conte, whose BALCO facility was at the center of a federal steroid investigation involving Barry Bonds, among others.
Byrd joins an increasingly long list of players suspended this year for PED use, including teammate Abraham Almonte, who received an 80-game penalty during spring training after testing positive for Boldenone, an anabolic steroid generally used on horses.
Wednesday's suspension comes at a particularly bad time for the Indians, who are currently without Almonte and star outfielder Michael Brantley. Byrd was slashing .270/.326/.452 with five homers in 34 games.