This is vintage, bought when we lived 2 blocks from Memorial Stadium.  Wild Bill Hagy was definitely a "thing" in Section 34 - greatest Baltimore Orioles superfan ever!  He led cheers where his body tried to form the letters - and that's what this shirt is about.  O-R-I-O-L-E-S!  BAWLAMER HON!

The Hanes tag says it's a size L 43-44 but I measured it and it's only about 38" around - so if you like it tight, call it a large.  If you want a looser fit, call it a Medium or Small.  It's 26" long and about 18" across the shoulders with very short sleeves.