That's exactly what James Gunn confirmed on Facebook, but quickly caught himself and stated it's for the sequel.
A fan asked Gunn: "Will Vin Diesel be back in GOTG3?"
Gunn replied, "Yes."
Another fan noticed the question and inquired about Gunn confirming Vin Diesel for Guardians of the Galaxy 3.
Gunn replied back, "No - he means 2 and that's what I was responding to. Stop it." Gunn also further commented: "Believe me I have to be careful because it will be picked up as my confirming 3."
"I knew for a long time what the story of the second one was gonna be," Gunn said, before teasing, "And the third one!"
"Guardians of the Galaxy Vol. 2" has a May 5, 2017 release.
Vin Diesel brought "I Am Groot" to life not only for English audiences, but for fans around the globe. Check out behind-the-scenes footage of Vin Diesel recording Groot in foreign languages for Guardians of the Galaxy: