Check baseball team over (4)
I believe the answer is:
stem
'check' is the definition.
(both can mean to control or stop)
'baseball team over' is the wordplay.
'baseball team' becomes 'mets' (New York Mets).
'over' says the letters should be written backwards.
'mets' back-to-front is 'STEM'.
(Other definitions for stem that I've seen before include "Stop or slow the flow of" , "Supporting structure" , "'Stalk, shank (4)'" , "Restrict - part of a plant" , "Staunch - support" .)