Player in the middle runs an 8 each time. Each time this player gets in the middle, a ball is thrown:
A throws (or plays overhand) the ball to B (in the middle).
B plays the ball back to A underhand and then runs around A until he is in the middle again.
A meanwhile passes the ball overhead to C.
C plays the ball overhand back to B.
B passes the ball back to C underhand and then runs around C until he is in the middle again.
Etc.
After 2-3 minutes, the player in the middle changes.
Variation:
To make it easier, player A and C can also have them throw instead of playing overhand. This can be an underhand throw/catch or an overhand throw/catch.
To practice standing still while playing/catching, you can also let player B throw and catch underhand.