Let's just start with the perpetual prefacing of all conclusions right now: We know it's early... so nothing is set in stone.
But with that said, you can find a few indicators of how guys play to shed some light onto what they're really going to become. Like with Perk: instances of added displays of quickness indicate that carrying less weight will be beneficial. And with Chuck: instances of constantly berating and humiliating our interns indicate that he's always gonna be an insecure douchebag.
And when you're looking for signs that someone is capable of handling the point guard position, you want to see that he recognizes what's happening on the floor quickly so he can find the open man. I saw that from Marquis Daniels last night.
In this video, Marquis does a couple of things:
1: He sees Trevor Ariza turn his head completely to Rasheed Wallace in anticipation of the pick and roll. Once he sees that, he knows that Trevor is over-anxious and ready to fight through the pick. Ariza's momentum is already setting up to go over Sheed's pick (notice the two shuffles of Ariza's feet as he's ready to slide past Sheed).... so Quis goes the other way and has Ariza easily beat.
2: Marquis sees that Scola recognizes Ariza is beat and slides over to cut off the baseline. As soon as Quis sees that Ariza is scrambling to recover and Scola is coming over to cut off the baseline, he knows Sheed is open. He gets Sheed the ball and Sheed buries the 3.
This all literally takes two to three seconds. It's impressive that he recognized what Ariza was doing and went the other way. A lot of guys who are new to a team would still try to execute the play as it was designed. But Marquis broke the play knowing that he could get the same result. Smart. You can see why guys are raving about his basketball IQ. The only thing that could have been better about that was the pass... which was too high. That's just a matter of being more comfortable with exactly where Sheed will pop on a play like that.
In the end, Daniels took advantage of a pretty good defender to set up his teammate for a bucket. He did something similar later in the game when he took the ball up the floor, drew the defense, and kicked it to Eddie House who buried a 3. Doc said afterward that Marquis had that play set up from half court because he recognized the matchups.
It's little things like this that make you see what the Celtics have been talking about. They're signs of a player who can read defenses and matchups and take advantage of them. If that's not the key quality of a guy who can handle some of the back-up point guard duties, then I don't know what is.