Zap2it.com — Sebastian Stan has his hands full with his role of Bucky Barnes/the Winter Soldier in the Marvel Cinematic Universe, but that doesn’t stop fans from clamoring to have him back on “Once Upon A Time.” His last appearance as The Mad Hatter was in the 2012 episode “The Doctor,” and he says a return likely won’t happen any time soon.

“It’s a hard question to sort of answer,” Stan tells Zap2it while promoting “Captain America: The Winter Soldier.” “I really enjoy that character and I have a lot of fun, and I enjoyed both of the showrunners and everyone on the show. Never say never. It’s very possible. At the moment, it’s not really on my radar, but you never know. I remain a big fan of everybody there.”

He does think that there is story left to be told with that character, though he says that any questions about what storylines those could be should be directed to “OUAT” creators Adam Horowitz and Edward Kitsis.

“There’s so many possibilities there,” Stan says of The Mad Hatter. “One of the things those guys did so well — out of the many things — is they just reinvented all of those characters in a new way. They reintroduced them to a whole new generation. The Mad Hatter was never like that in just the cartoon. It remains to be seen.”

“Once Upon A Time” airs Sundays on ABC at 8 p.m. ET/PT. “Captain America: The Winter Soldier” hits theaters on April 4.