Doug Gottlieb says his Twitter shot at Andrew Luck's retirement was supposed to be a joke ...and wants to make it clear he's actually a big supporter of the ex-NFL QB.
The Fox Sports Radio personality got a TON of flak for his shot at Luck on Saturday ... when he said "Retiring cause rehabbing is 'too hard' is the most millennial thing ever #AndrewLuck"
Gottlieb addressed the backlash on Monday ... saying the tweet was supposed to be funny, but people took it WAY too seriously.
"I'm a smart ass. I always have been.