There's every chance that we'll see Marshall in a Cardiff City shirt again.
Look at Wigan. At the end of last season many were positive that the likes of McManaman, McArthur and Maloney would be back in the Premier League come August - but they're still there. Yes, Marshall is in a different league, but add the fact that he's settled and was recently willing to sign a new contract, and him staying is a plausibility.
I truly believe that he deserves a move to a bigger club (Spurs if Lloris goes, for example), but this summer will be a long waiting game.