Lamar Odom: PLAYYYY BALL ... Hits College Baseball Game

Big outing for Lamar Odom this weekend ... the ex-NBA star hit up a college baseball game in L.A. -- and the kicker, we're told he was essentially all by himself.

Odom was spotted at the Cal State Northridge baseball stadium Sunday -- where the Matadors took on CSU Bakersfield. We're told Odom stayed the entire game and was rooting for the home team.

One person we spoke with says Odom appeared to arrive by himself -- no Kardashians were with him -- and met up with a guy who's believed to be a trainer at the campus training facility.

There were rumblings at the stadium that Odom was playing basketball ... though we haven't confirmed that yet.