Superman's Red Trunks

So I have a question. Has there yet been an actual in comic explanation as to exactly why Kal-El is sporting his red trunks again. It was briefly mentioned in Brian Michael Bendis’ Man Of Steel that some “in-universe” bystanders noticed he was wearing them again but that was about it. I’m just honestly curious.

He gave Lois his old costume when she headed to space. Left him with the red trunks version.


Thank you! I mist have missed that.