Canelo Alvarez just got slapped with a 6-month suspension for his failed performance enhancing drug test that he blamed on tainted meat ... the Nevada Athletic Commission just announced at a hearing in Vegas.

The commission only took minutes to deliberate on Alvarez's case ... ultimately giving him half of a maximum 1-year ban, noting that he's been "cooperative with investigators."

Canelo's May 5 rematch with Gennady Golovkin has already been scrapped ... but, this opens the door for Alvarez vs. Golovkin 2 to happen in September -- a time frame GGG previously told TMZ Sports he's gunnin' for. 

As we previously reported ... Canelo got popped for the PED Clenbuterol in March from a test administered on Feb. 17. Because his ban is retroactive to the date of the test, Alvarez is eligible to fight as soon as Aug. 18. 

Canelo has maintained his innocence throughout the process ... blaming Mexican beef for pumping 'roids into his veins.

FYI, GGG just announced Canelo's replacement for their May 5 fight -- he's facing Armenian-American boxer Vanes Martirosyan.