I don't think you can start Calhoun at shooting guard. He's hardly played any shooting guard in his two years here, and given he struggles to stay in front of small forwards, it's probably not a great idea. Hopefully Purvis, Samuel, and Hamilton can man the brunt of the ball-handling duties better than they did yesterday. Maybe with a little extra notice they'll handle it better than they did being thrown into the fire.
I'm curious to see if a lineup featuring Purvis at point guard with Calhoun and Hamilton at the wing and Facey and Brimah up front could function with any degree of competency. The initial protest is, "no way in hell Purvis can handle the point", but I don't know how much worse he could be than what Samuel was yesterday - Purvis was basically the de facto point guard for most of crunch-time yesterday, and he's going to have a better chance succeeding in that role with Samuel on the bench.