NFL's Donald Penn Unloading $5.2 Mil L.A. Mansion After Move to Redskins

Donald Penn's got a new home in the NFL ... and now he's trying to get rid of his old home in L.A. ... 'cause the Washington Redskins lineman is selling his $5.2 million mansion!!

TMZ Sports has learned ... the 36-year-old Pro Bowl tackle is parting ways with his 8-bedroom, 11-bath Encino pad ... which comes with a private home theater and a freakin' walk-in shoe closet!!

If that ain't enough, the 11,000-square foot place also has a game room, private gym and a sauna ... as well as 2 private guest suites.

Oh, yeah ... AND it's got a pool!!

Penn was an undrafted free agent out of Utah State ... but grinded his way to a 13-year career with the Vikings and Raiders ... and made more than $60 MILLION along the way.

So, why did he have a home in L.A.? Penn was born and raised in SoCal ... and was a star standout at St. Bernard HS.