Drummer Travis Barker and former Blink singer/guitarist Tom DeLonge got the rumor mill turning Thursday with this playful Twitter exchange ... but sources close to the band tell us Travis and Tom were just trolling each other, and they don't wanna mislead their fans, who were all just unsuspecting victims for a few hours.

We're told Travis and Tom privately communicate all the time, and this was just fans seeing their relationship on social media.

There is some good news ... Travis has finally been medically cleared to drum after getting treatment for blood clots, and he'll perform with Blink on Oct. 26 and 27 in Vegas!

But, Tom won't be onstage ... it's still Travis, Mark Hoppus and Matt Skiba.