Welcome back, Dwight Howard.

It has been a while since we've witnessed Howard anchor a top defensive team. To be exact, the last time a Howard-led team cracked the upper third in defensive efficiency, he was starting next to Jason Richardson for Orlando in 2010-11. It's been that long.

But here we are in 2015, almost three years since his lumbar microdiscectomy (translation: serious back surgery), and the Houston Rockets rank second in defensive efficiency in the NBA. Who saw that coming?

If you're looking for a dark-horse defensive player of the year candidate, it's Howard.

The Rockets' resurgence on that end of the floor has been one of the league's bigger surprises after they traded away a rim protector in Omer Asik and overhauled the roster with an oddball crew of youngsters in the offseason. The addition of Trevor Ariza on the wing helps, and so does James Harden's renewed dedication to that pesky other half of the game.

The Rockets aren't sniffing a playoff spot in the West without Howard -- a three-time defensive player of the year -- rescuing them on the back line. Let's take a look at Howard's candidacy and the other candidates for DPOY.