James Harden's absence from the Philadelphia 76ers' season-opening road trip continues to draw attention.

The NBA is currently investigating his availability to "determine whether an approved reason exists for his lack of participation," ESPN's Adrian Wojnarowski reported.

The 10-time All-Star won't play when his team opens their regular season against Milwaukee Bucks on Thursday night, fans learned on Wednesday. He's not expected to be present for Philadelphia's matchup against the Toronto Raptors on Saturday, either.

Hours before news of the league's probe broke, Chris Haynes reported that Harden attempted to join the Sixers for both road games. He was reportedly stopped from getting on the plane by a security official.

This came after Harden had been away from the team for 10 days. The guard reportedly no-showed at practice to spend time in Houston.

He showed up to Philadelphia's facilities with his bags packed on the day the team was schedule to leave, prompting coaching staff's decision to keep him in Philadelphia so the team wouldn't be distracted, according to Yahoo Sport's Vincent Goodwill.

Harden was under the impression the team's mention of him staying home to work out was only a recommendation, Haynes' report said.

This story will be updated.