Arsenal has always been convinced that Mesut Özil is a soccer genius. The club was sure enough that it tripled its record transfer fee to acquire him in 2013 and remained certain enough to make him its highest paid player with a contract extension last year.

But after investing over $100 million in him over the years, Arsenal is grappling with a much more perplexing question than whether or not Özil is supremely gifted. (For the record, he is.) The more pressing question is whether the most talented player in their squad is even worth starting.

The answer isn’t as clear-cut as it seems. Özil has become an enduring enigma. At his best, there are few passers in the world like him. He is able to trace paths through defenses that will make you believe he sees the universe’s hidden dimensions. His touch is so deft that he can literally spit out a piece of gum, juggle it with his feet and knock it back into his mouth.

But at his worst, Özil is practically invisible. He fades quietly into the background, shoulders slumped, while the match unfolds around him.

Former Arsenal manager Arsène Wenger tortured himself for five years wondering why Özil couldn’t take over games. He never came up with an answer. These days, Wenger’s successor Unai Emery doesn’t even seem terribly interested in picking up the puzzle.