It's certainly disappointing, however I suppose he's just going to have to wait for his chance which I'm sure he'll get at some stage. To be fair he has been playing with an injury lately which has hampered him in his recent performances against Birmingham, although he played well against Spurs and Chelsea. Back to Walsall made a good point that Trap has nothing to gain from seeing Wardy get ripped by Kaka which in the long term could be more damaging to his confidence. He still has a bit to learn, so maybe just concentrating on learning his trade in a relatively new position will do him good and help ensure that he gets another chance to learn in the top flight next season if we stay up.
My only concern is that this is not another case of the "if your face fits" syndrome which has been slightly endemic of Trap's reign. He seems to have a habit of favouring certain players (Miller, McShane, Kelly etc.) at the expense of testing others (I'm not sure how much Givens might have to do with this who seems to have based his whole managerial career on petty prejudices). Also, Wardy is definitely more of a roving full back, overlapping regularly, which may not be Trap's cup of tea, as he seems to prefer his banks of four.
The only other alternative is that he is planning to play O'Shea at left back when he returns, which if so I hope is to accomodate Foley (or Coleman) as opposed to McShane or Kelly.
With a bit of luck, this will just be a swansong for Kilbane as a fitting tribute to end his career and an opportunity to showcase the next generation (McCarthy/Cunningham) to show young lads of a similar age what can be achieved if they apply themselves.