EXCLUSIVE
Keyshawn Johnson will NOT be prosecuted for domestic violence ... TMZ Sports has learned.
Law enforcement sources tell us ... the L.A. County District Attorney has rejected the case ... after cops determined the arrest was an overreaction by someone who was speaking on the phone with Keyshawn's baby mama.
TMZ broke the story ... Keyshawn was arrested last month for allegedly wrestling a cell phone out of the woman's hand ... slightly injuring her hand in the process. We're told an argument had erupted when Keyshawn saw his GF reading texts from someone as they were speaking.
We're told it was all triggered by the person on the phone who heard the argument between Keyshawn and his baby mama that ended with him throwing the phone to the ground and breaking it. The person who was on the phone heard the argument, became alarmed and called 911.
As for his baby mama's injury -- authorities now say she sustained a very small scratch on her finger while trying to hold on to the phone and it amounted to nothing.
Law enforcement sources say when L.A. County Sheriff's deputies arrived ... both Keyshawn and his baby mama were surprised and no one wanted to pursue charges. Nonetheless Keyshawn was arrested.
We couldn't reach Keyshawn's lawyer, Shawn Holley, for comment. 
