No. Conor can't lose from this fight. He's taking on the best pound for pound boxer on the planet. To even bring up Mayweather's name shows Conor is not only special, but has balls of steel. But he's expected to lose.
Take it from me, a Conor fan. Conor WILL get TKO/KO'ed in this fight. Not because he's got a weak chin and Mayweather's "pillow fists" are irrelevant in this. Mayweather is the best in the world of boxing and there's no way Conor can last 12 (or even 5) rounds against him. He will get schooled, given a boxing lesson and humbled. But he has the nuts to do this and that, in itself, is worthy of huge praise.
For the payday that Conors about to get anyone would jump at the opportunity to fight Floyd.