Top draft pick Markelle Fultz is part of the reason for the optimism surrounding the upstart Philadelphia 76ers this season.

A 6-foot-4 combo guard, Fultz was touted in the draft for his ability to handle the ball and run the offense or spread the floor and create his own shot. The most complimentary draft comparisons likened his game to James Harden's.

However, through two preseason games with the 76ers, something has been off with Fultz's shooting form. It was readily apparent during a missed free throw in a preseason game that went viral on Monday night.

Fultz shot just 65% from the free throw line in college, but he was an overall good shooter with a smooth, square form. On this dreadful free throw attempt, Fultz looked like he was pushing the ball out in front of him.

Biggest problem with Fultz free throw is that he starts it at shoulder height. Needs to start at waist level for rhythm and POWER pic.twitter.com/CExnUgao4r — BBALLBREAKDOWN (@bballbreakdown) October 9, 2017

This is just one free throw, but according to The Ringer's Kevin O'Connor, it hints at a larger problem with Fultz's shoulder. Fultz has apparently been dealing with on-and-off shoulder soreness during preseason, and comments from Sixers coach Brett Brown after Monday's game don't make it sound positive.

"I think [his shoulder] is affecting him more than he lets on," Brown said. "You can tell with his free throw, trying to get that ball up. It’s far out from his body. He’s been working on trying to get that thing rehabilitated. And the lack of the quantity of his 3-point shooting may be a sign that it’s hurting a little more than he’s letting on."

Likewise, the vagueness with which Fultz described the injury is not promising.

"I wouldn’t say it’s making any effects on the floor, because I’m playing through stuff like that. Every day I come in, we just talk to the trainers and do stuff for it and just get better."

According to O'Connor, when Fultz first showed off a funky shooting motion in training camp, he said he was messing around, but Brown said he'd like to see Fultz get back on track with his shot.

Fultz's two preseason games don't offer much in the way of evidence about how it's affecting him. In his first preseason game, he shot 2-of-13 from the field and looked out of sorts. In his second game, he shot 5-of-11 for 12 points on a bevy drives to the hoop. He's 0-for-3 from three-point range so far.

Again, while it's just one shot in a limited sample size, Fultz's release below seems to be high and away from his body.

On an almost identical shot in college, his form looked tighter and more square.

The change is enough to have some in the NBA world concerned.

If Fultz is just messing with his shot because of shoulder soreness, then perhaps the concern over the change will go away when it's healed.

The larger concern is how long that will take and if it messes with his shooting form long-term. Fultz was a good shooter in college and likely didn't just forget how to let the ball go. But with the NBA season approaching and Fultz's shoulder perhaps hurting more than he's letting on, the Sixers should be concentrated on getting him healthy and back into rhythm.