I wouldn't necessarily say dogs 'need' to play...Huney doesn't. She's more happy to be out of the way of the play and has never played with toys at all.
We've tried and she just doesn't seem to care for them.

Now every once in a while if Bon and Roxey are running around and playing in the yard she'll run after them for a few seconds, then turn and walk away Guess she only needs a few seconds of play

I think if she's happy that's all that counts