The Republic of Ireland international is worried about his place in the Euro 2016 finals.
The arrival of Sam Byram has seen the Republic of Ireland international's chances of regular football take another knock and he confirmed to London 24 that he is open to the idea of leaving the club.
“I need to go and play games.
“The Euros are in the summer. I need to be playing games to try and get into the next squad for the friendlies. Then we can see what happens from there but I need to be playing. Ireland hasn’t been to many major championships, so this is a big deal.
“I will have to see what the manager thinks. If he sits me down and says he wants me to go out on loan then I will look at that.
“It is down to the manager, if he wants me to hang around here then that’s what I will do. But if he wants me to go out on loan, then I will look at that.”
O'Brien is one of those players who is not yet assured of a place in Martin O'Neill's squad for the European Championships in France this summer and will know he will need to be playing regular football if he is to have any chance of making the cut.
O'Brien, who can play at both left and right-back, featured just 11 times for West Ham last season and has played just five times this term with West Ham - and not featured since the Europe League tie with Astra Giurgiu in July.
But it is also likely he might be asked to stick around by West Ham manager Slaven Bilic - after Arsenal loanee Carl Jenkinson suffered a potentially season-ending injury at the weekend.