Charlie Sheen -- All Geared Up For Sportscasting Debut

Vin Scully, Harry Caray ... Charlie Sheen?!

That's right ... the Warlock is moments away from getting behind the announce desk to co-host ESPN's Sunday Night Baseball pre-show -- his favorite team the Reds are playing.

Shortly after arriving Sunday afternoon to the Great American Ballpark in Cincinnati ... Sheen ran into a high school baseball team who were all fans of his -- so they posed together for a pic.

In case you weren't paying attention ... ESPN is letting Charlie Sheen go on live TV.