23 Portsmouth signings that have failed since Michael Eisner's Fratton Park takeover: gallery

There’s no guarantee that every bit of business conducted in the transfer market will prove a success.

Indeed, for every Colby Bishop, Lassana Diarra, Ricardo Rocha and Gavin Bazunu, there could easily be a Djimi Traore, Theofanis Gekas or Mike Williamson lying unexpectedly in await, too.

There’s no scientific explanation why a transfer can turn sour for one and be a huge success for another.

However, the nature of modern football, with players and managers changing clubs so often, means there's always going to be those who struggle to perform in a short space of time.

Like the majority of clubs, Pompey have found that out for themselves in recent years.

And with another transfer window on the horizon, the pressure will once again be on the Blues to get it right.

But what lessons can be learned?

Well, if the list below is anything to go on, there’s plenty of case studies to refer back to.

Of course, not everyone included is a bad player. It just didn't work out for them at Fratton Park for whatever reason.

The list doesn’t include anybody presently at the club. But let us know if there's anyone you think escaped it who deserves to be on the list from the Michael Eisner era.