I don't know general. If Djokovic, Murray, and Federer are not playing then Rafa has a chance.
I guess there is always Wawrinka. But who else, the Lost Generation like Dimitrov, injured Raonic, always injured Nishikori? Or maybe the Next Generation, like Zverev and Kyrgios?
It seems that Rafa could do well on the clay if he puts in some effort. He's the greatest clay warrior of the generations. That has to count for something.
Respectfully,
masterclass