LeBron James is upset. This much we know. How else do you explain the meme he posted Monday night to Instagram of a cartoon clenched fist?

It’s unclear, however, what exactly provoked James. Maybe it’s the Cleveland Cavaliers’ early-season struggles, or maybe it’s the Boston Celtics’ nine-game winning streak behind the solid play of James’ former teammate, Kyrie Irving. Either way, folks on social media can’t help but wonder.

Skip Bayless and Shannon Sharpe addressed the topic Tuesday morning on FS1’s “Undisputed,” and Bayless is among those who believe James’ apparent displeasure stems from watching Irving succeed with Boston.

Irving scored 35 points Monday as the Celtics defeated the Atlanta Hawks 110-107. Boston’s win came one day after Atlanta defeated Cleveland 117-115, dropping the Cavs’ record to 4-6.

Irving demanded a trade from Cleveland over the offseason because he no longer wanted to play in James’ shadow. Now, the Celtics look like a legitimate threat to dethrone the Cavs in the Eastern Conference.

If James really is frustrated, who could blame him?

Check out the video below for Sharpe and Bayless’ full discussion.

Thumbnail photo via Ken Blaze/USA TODAY Sports Images