There were whispers of Deuce leaving Tottenham all throughout this transfer window. Paulinho was brought in to strengthen the midfield. Roberto Soldado just became the starting striker. And if the Bale for Di Maria and Coentrao move had actually materialized (which I doubt will at this point), Dempsey leaving would have been completely understandable
That's not to say that this move is a complete mystery. Dempsey could have stayed, but he would have had to battle for a starting spot at any of the positions his versatility allows for. Personally, I would rather have him on the field rather than Moussa Dembele, but that did not look likely.
The real "head scratcher" is why he chose to come back to MLS rather than stay in Europe. It actually makes perfect sense. Critics will look down on this decision because of the fact that Deuce is 30 years old, has a lot left in the tank, and that he has already proven so much in his seven years in the Premier League to regress to MLS. While I agree that he could have stayed abroad and found another team, it would not have been in his best interest. Let's break down his options:
Staying in England
Let's throw the Top Four out the window because Manchester United, Man City, and Chelsea are all set at his position. A case could be made for Arsenal, but with Cazorla having a strong season, and Arteta and Wilshire manning the other central roles, playing time would certainly be an issue.
That leaves non-Champions League teams as his option in England. Teams like Everton, Fulham, even my struggling Liverpool could have found space for him on the field, but not playing in Europe's highest competition defeats the purpose of staying in England.