MLB superagent Matt Sosnick -- whose agency reps huge stars like Pete Alonso -- was arrested for domestic violence for allegedly choking his wife in front of their young daughter ... and now she has a restraining order against him.

FYI, Sosnick is a big deal in Major League Baseball ... his powerful SCK Sports agency reps All-Stars like 2018 AL Cy Young winner Blake Snell, and Mets slugger Pete Alonso ... as well studs like Jay Bruce, Mitch Haniger and Blake Treinen.

Matt initially gained notoriety in the early 2000s for repping ex-Marlins star Dontrelle Willis, who actually got Sosnick's agency's logo tattooed on his arm during his pitching days.

But now, Matt's wife, Erica Sosnick, has filed for divorce from the 50-year-old -- alleging he roughed her up during an Oct. 8 incident.