Wiz Khalifa is getting ready to throw that high cheese when he takes the mound at the Pirates game ... 'cause the rapper says he's planning on being "stoned af" for the ceremonial first pitch.
The Pittsburgh native -- who's in town for his "High School Reunion" tour -- will do the honors before his hometown team hosts the Cleveland Guardians on Monday ... and he's got a perfectly on-brand strategy in place ahead of his big moment at PNC Park.
"Finna get stoned af and throw this first pitch at the pirates game," Wiz tweeted to his 36 million followers.