With Wladimir Klitschko calling it quits, there's another fighter who wants to step up and take on boxing superstar Anthony Joshua -- Stipe Miocic!
Wlad and Joshua had been working on a rematch after that great fight back in April -- but WK announced his retirement early Thursday morning ... so those plans are off.
But Stipe wants to take his place ... and with Conor McGregor fighting Floyd Mayweather, he clearly thinks there's a chance.
"Looks like your schedule is wide open," Stipe told Joshua on social media .