When we last saw Ezra Bridger he was being carried off into the Unkown Regions by some hyperspace whales after battling Thrawn. Whether or not he survived remains a mystery, but if he did, he’s one of the few in the timeframe of season two of The Mandalorian who would still be wielding a lightsaber.
With Mando and The Child still on the run, they could find themselves way out in the Unkown Regions. It is very possible they settle on a planet and cross paths with a mysterious old Force wielder. Ezra would sense the strong presence of the Force in Baby Yoda and surely seek him out. During their palaver, they could get tracked down by Moff Gideon. It is at this moment that the epic lightsaber action could ensue.
Bridger could be rusty with his blade, but would still make fast work of the Moff. It would be a surprise to be sure but a welcome one if Ezra Bridger’s story was continued in The Mandalorian. While unlikely, the show has already given us a bunch of twists we didn’t see coming so anything is possible.