Many coaches have their hitters do some version of one hand drills with a short bat either off a tee or soft toss. Some do top hand only, some do bottom hand only, and some do both.
To aid in these drills and possibly help prevent injury during these drills the hitters must have a proper grip on the bat at all times for control of the bat's barrel.
I highly recommend using The Bat Jack Grip Trainer while doing these drills.
You can find it at The Bat Jack Grip Trainer - Baseball / Softball Swing Aid Develops Proper Bat Grip For Hitting
To aid in these drills and possibly help prevent injury during these drills the hitters must have a proper grip on the bat at all times for control of the bat's barrel.
I highly recommend using The Bat Jack Grip Trainer while doing these drills.
You can find it at The Bat Jack Grip Trainer - Baseball / Softball Swing Aid Develops Proper Bat Grip For Hitting