I think that's probably correct - but for different reasons.
He only played about 20 odd games for Fulham last season due to fitness and only 5 so far this season for us.
Looking back over the time since he debuted in 2016 he's not averaged more than about 20 odd games a season.
I suspect the medical he had when joining Spurs showed no significant issues ongoing but its clear there are, and ultimately we can't afford to have a dedicated squad place to someone who's fitness means he might only be fit for 20 odd games a season - its not really been an issue this season as not being in europe means we've only be playing once a week, but its quite possible we would not have signed Werner on loan had Solomon been fit.
Signing him probably seemed low risk - a free transfer with at least average fitness - but its not turned out that way.
Question is how we might off load him given he's played so little and even if he is fit enough in a couple of weeks I suspect he'd only get minutes off the bench. Maybe a short loan over summer to a league that's playing then like Sweden or even a south american league ?
That way he might be attractive to a lower PL or overseas club, but rumoured to be on £60k pw (£3m pa) he's going to need to find an affluent club.