PHOENIX — Tension appears to be brewing on the Sky. Point guard Skylar Diggins posted an Instagram story that read: "Now I'm coming off the bench?????? Cool." She followed with a video, saying: "And the crazy part about it is that I've been quiet. I've been so good and quiet. I've been so good and quiet." The Sky are preparing to play the Mercury on Tuesday in the second game of a four-game road trip. Diggins has started every game she has played this season, but she hasn't hidden her frustratio