KANSAS CITY, Mo. (AP) — Royals pitcher Jeremy Guthrie apologized on Twitter to the Orioles for wearing a T-shirt to his post-game news conference Tuesday night that read, “These O’s Ain’t Royal.”

Guthrie wore the shirt, a twist on the Chris Brown song “Loyal,” after Kansas City beat his former team 2-1 to take a 3-0 lead in their best-of-seven AL Championship Series.

The shirt touched off an avalanche of criticism toward Guthrie. Along with offending many Orioles fans, the shirt also ignited controversy across social media platforms because of the vulgar and derogatory nature of the song’s original lyrics.

Guthrie, a prolific user of social media, said in his apology early Wednesday that he did not consider the reaction the shirt might generate and did not intend to offend.