I doubt it. The Undertaker's injuries have really caught up with him over the past couple of years. He'd been known to work hurt much of the time, often pushing back taking time off to rest up or to have surgery. But, as he got older, injuries kept piling up and eventually overtook him. Taker suffered a shoulder injury a while back that he waited too long to have surgically repaired and, because of that, doctors informed him that he'd probably never regain full strength in that shoulder even with surgery.
Taker said himself in a promo that all he has left is the streak and that's true. He's a 7 time World Chammpion, a 7 time tag champion, Royal Rumble winner, been involved in some of the most memorable feuds, matches, angles & storylines in WWE history, he's possibly the most respected and well thought of veteran in wrestling today. Taker's legacy is already secured and has been for a long time now. He's one of the rare talents that comes along in wrestling that eventually becomes so respected and revered by insiders and fans that he's completely above championships. At WM, Taker has defeated wrestlers that have, overall today, won a total of 76 World Championships.
The streak has become a special attraction for WrestleMania and, I think, the idea is that Taker will continue to wrestle only once a year at that event. WWE has built Taker up over the years as this mystical character, almost like something of a force rather than a man in some ways, and having him show up once a year only to defend his streak makes people even more excited to see him. There's only one first day of summer, there's only one 4th of July, there's only one Christmas Day and only one time when Undertaker laces up the boots.
If by some chance Taker does wrestle, it'll probably be in a tag team or six man tag match that would probably be a ratings draw and would allow them to protect Taker while his teammates did most of the work.