It’s really as simple as that. While the injury had a part to play, the aforementioned reason is probably the biggest part of it all right now.
While you can count on all of those guys to do what Garrett can do for you right now, there may come a point and time throughout the remainder of the season where you need a shot-maker.
Kyle Guy is just that. On top of being able to just make shots though, Guy has proven to be able to make tough shots that he shouldn’t be able to hit.
That very ability may come in handy when the Miami Heat most need it. In conclusion, the fact that they really like something about Guy is apparent at this point.
It also emphasizes one more thing about the NBA, in general. Scoring, shooting, and shot-making are held at a premium and if you can do that with regularity, then you can certainly find yourself a job in the big leagues.