#2 Comedy tour ending

This could perhaps be the most logical reason! Dolph Ziggler's first love is wrestling, but he stepped away from the ring to concentrate on a career in standup comedy, performing at several venues across the USA over the last few months.
The tour was to end on March 21st, but more shows have been added over the last few weeks, with him set to appear twice at the end of this month. We aren't quite sure if this is the end of the tour, but if it is, it makes complete sense as to the timing of his return to WWE.
Did you know a top WWE Superstar just wrestled outside the company? More details HERE
He last feuded with Drew McIntyre on RAW, following an alliance between the two which ended. The Showoff had the last laugh as he eliminated McIntyre at Royal Rumble in the men's Royal Rumble match, which was his last appearance in WWE till this week's SmackDown Live.