Michael Strahan Blindsided by Ripa Taking Divorce Cheap Shot

The gloves are off ... and Michael Strahan got that message loud and clear when Kelly Ripa dropped an unscripted jab at him over divorce, TMZ has learned.

Sources connected to production tell us Ripa's intro to a segment about divorced couples was a total shock to Strahan. If you missed it -- Kelly innocently turned to her co-host and said, "So, you've gotten divorced ..."

We're told the look of shock on his face was 100% authentic.

Of course, both Kelly and Michael knew they were doing the segment, but we're told he had NO IDEA she was going to raise his divorce as part of it. If it looks like a cheap shot, that's exactly how Michael and others on set took it ... according to our sources.

Strahan played it off on the air this time, but these last 2 weeks -- before he jumps to 'GMA' full-time -- are gonna get interesting.