1
general::
Phrase(s): in there pitching
Fig. trying very hard. • Bob is always in there pitching. • Just stay in there pitching. You’ll make some progress eventually.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Exerting one's best effort, trying actively. For example, After the flood, everyone was in there pitching to clean up the streets. This metaphor alludes to the pitcher's important role in baseball. [Colloquial; c. 1940]
American Heritage Idioms