The image is appropriately tagged; sources are reliable.
"Greene learned how to pitch at the instructional facility and appearing in several youth showcase events": inconsistent tense.
Changed to and appeared to fix tense.
There are uncited sentences. I'm not sure the "average fastball" velocity deserves a place in the article anyway, given that we're in the middle of the season.
Everything beginning with the May 15 sentence was added by other individuals. I have since cleaned up that section to include only relevant, cited information: a large performance shift in June, an MLB record, and a recent injury.
Per WP:EL, Instagram and Twitter links shouldn't be included in the external links section.
Removed.
No career statistics section?
Baseball articles do not typically have these unless the player is no longer active. In that case, career statistics are usually rendered in prose. See Tyler Skaggs, an FA, for an example.