Stewart is heavily linked with a move to Plymouth to join up with new boss Ian Holloway.
Speaking about missing the tour Stewart said
'It's disappointing but I knew it was happening - it's not as if they have sprung it on me. I knew about it a few weeks ago. Now I am just going to get really fit for myself. I have always got myself fit and the only disappointing thing is I won't be playing games with the lads on the trip and getting match-fit.'
Also left behind was Dean Grubb as he recovers from a broken leg.
Two trialists have joined the tour - ex-Torquay midfielder Morike Sako and Frenchman Nicolas Gindre.