I'm one who thinks (and I am a SUPER SCIENTIST so I know everything) that outdoor spaces are probably pretty ok, and even those crowded beaches aren't too much to worry about (it's the crowded bars near the crowded beaches that are more of a concern), relatively speaking, but an old baseball stadium is a bit of a hybrid indoor-outdoor facility with a lot of bottlebecks,
and 7000 people are 7000 people.
The Chicago Cubs have devised strict protocols they believe would allow 6,000 to 7,000 fans to safely attend games at Wrigley Field midway through this pandemic-shortened season — in groups of two, four and six and with designated gates and staggered entry and exit windows.