Ozil had missed Arsenal's previous three games with a knee problem, before being named on the bench against West Brom.
However, club legend Keown believes Ozil didn't start the game for a very different reason.
He told BBC Sport: "I think he loves playing football, Sanchez, I don't see there's an issue with him.
"Ozil of the two players, are they going to sign, aren't they, is the one I wouldn't trust as much mentally, and I believe he's not playing tonight because the gaffer really can't trust him anymore.
"I think it's a huge story that Ozil doesn't play tonight.
"If you look at their pre-seasons, Ozil wasn't in the German squad in the summer, he came back on the very first day of pre-season, and didn't then start the season, there was a bit of suspicion around him
"Last year he went missing for a couple of months and I think that's his tactic in terms of getting away from the football club.
"I don't know - but I have a feeling that he's going to take his reliability away from selection."