On discovery of such a problem, is it not possible to write in clauses to the effect that the fee is dependent on the number of starts a player makes? I can understand the club's hesitance if there is a genuine problem. He looks a great player, that's for sure, but let's face it Klopp's style of play is going to expose a player to a lot of mileage in a physical league.
You usually pay for a transfer using instalments, so you can write in performance targets, like after 100 appearances etc, but if a deal has already been agreed, that mean's going back to re-negotiate, which doesn't sound an easy option with the Lyon owner!
Reports are we pulled out of the deal and didn't try to renegotiate, so sounds like we will not be going back. I guess after the Andy Carrol & Sturridge deals, we have learnt since buying players who have had bad injuries.
It can backfire though, didn't we turn down Loic Remy after a medical, then he went on to do well? but the way Klopp expects the AM to work, a player with a weak knee could have long term problems.
