In whole, you may see me in the competition, or on the street.
Remove my front part, you may see me in the body, or on the lawn.
Remove my rear part, you may see me in the prison, or in the grocery.
Remove my middle part, you may see me in the sea, or on the stage.
Remove my middle part again, you may see me in the baseball game, or in the university.
Who/What am I?
Chances to see in places(based on my thoughts :P):
competition: LOW to HIGH, positive correlate to competition schedule.
street: LOW, but vary in cities or countries.
body: VERY HIGH.
grocery: LOW, but vary in locations.
baseball game: LOW to MEDIUM.
The answer could be a noun or an adjective. Also the answer has 2 main meanings which are almost on the contrary.