The two were spotted out together on a social distancing coffee run in L.A. on Wednesday -- and our sources tell us it's the 3rd time they've been spotted together in recent days.

One witness described the most recent outing this way ... "They very much seemed lovey-dovey. He even opened her car door."

Of course, Rudolph was the QB for the Pittsburgh Steelers in 2019 -- and was famously on the receiving end of that Myles Garrett helmet attack!

But now, he's in L.A. -- he's been working out in Beverly Hills -- and apparently getting close with Hannah Ann.

Here's the twist ... Hannah has been teasing to media outlets that she's been involved in a "quarantine fling" with a "mystery man" but has not revealed the mystery guy's ID yet.

So, is Mason the fling?!

We reached out to Hannah's camp for comment -- so far, no word back.

Hannah may have a thing for football players -- she was reportedly spotted hugging Jacksonville Jaguars QB Josh Dobbs at a bar in Tennessee back in early March.

As for her run on "The Bachelor," she was engaged to Peter Weber on Season 24 -- but he broke it off to be with Madison instead.

Hannah became a huge star after the show -- but if she's serious with Mason, it could kill her chance to be a future 'Bachelorette.'

Decisions, decisions!!!!