O’Brien had a short loan spell in the MLS last season and is surplus to requirements at Nottingham Forest this summer.
However, the club have so far failed to shift him despite interest from several clubs in the Championship.
Leeds are interested in getting their hands on him before Friday’s transfer deadline but are only keen on signing him on loan.
It has been claimed that Coventry City, Ipswich and Middlesbrough have also made enquiries for the midfielder.
All three clubs are in the market for midfield men and O’Brien is a player they are interested in signing.
However, like Leeds, the other three clubs are also interested in only signing him on a loan this summer.
Nottingham Forest would prefer to sell him and want most of the £10m they paid to sign O’Brien.
However, for the moment, none of his suitors are interested in offering anything more than a loan bid ahead of Friday’s transfer deadline.
