James Harden -- Officially Jumped In to Kardashian Klan ... Bad News for Nike? (VIDEO)

James Harden got dragged through the Kardashian ringer -- a full weekend of family events -- and came out the other side, so he's official ... in our book, anyway.

Khloe Kardashian and her man were swarmed by photogs on the way out of Kylie Jenner's 18th birthday party Sunday night at Bootsy Bellows. He was also at the Friday night dinner in Malibu.

Here's the thing ... Harden doesn't look the least bit annoyed -- despite the standard Kardashian pap crush -- so, we're thinking he's all in with the 'K' klan ... and maybe Adidas too.

Remember ... Harden's spending a lot of time with Kanye West at these family functions, and since Adidas already makes Yeezys -- you gotta figure Kanye's talking up the company's $200 million offer to James.