Montrezl Harrell is working on his stretch four skills

Montrezl Harrell has been working on his three ball. And while the results thus far have fallen short, the sky's the limit for the Louisville product if he can continue to improve his shot.

One of Montrezl Harrell's biggest weaknesses last season was an inability to stretch the floor. The big man took 90 percent of his shots within 10 feet of the bucket. It's one of the reasons the Rockets ran out and signed quintessential stretch four Ryan Anderson to a four-year, $80 million deal.

A modern NBA offense requires a power forward who can drift out to the three-point line and cash a long ball, and an offense led by James Harden, who makes his living driving inside, needs spacing and big man who…