The young midfielder, who celebrated his 20th birthday during his time with QPR, was only able to make three appearances for the Superhoops following a hamstring injury midway through his spell.
A fortnight ago he returned to Loftus Road fully fit, but could not find a place in the starting XI despite a number of injuries to key Rangers players.
With the purchase of Jamie Cureton, Marney has found himself pushed further down the pecking order and Ian Holloway has decided not to seek an extension to the deal.
Elsewhere, midfielder Richard Johnson has confirmed that he hopes to be fit for the weekend trip to Tranmere.
The Australian international suffered a sprained ankle against Peterborough and looked doubtful for the game at Prenton Park - but he believes he is on course to travel.
He said: "I'm going for a scan on the ankle, but it's really just precautionary. I should be alright for the weekend."
Clarke Carlisle is also battling to return after suffering a similar injury against Posh, whilst Martin Rowlands is training again tomorrow after sitting out Friday night's draw.