Brown made his Manchester United debut in 1998 but has since fallen down the pecking order at Old Trafford. After a reported bust-up with Sir Alex Ferguson last season, the 31-year old is rumoured to be on his way out of the club.
Republic of Ireland international Gibson has endured a difficult season at United. With many fans seemingly turning on the 23-year old United would listen to offers to the player they value at £6 million.
The pair may even be used as a makeweight in any deal for long-term target Jordan Henderson. United have been linked with the midfielder before but Liverpool are also thought to be readying an offer.
Interest in Brown is high with Everton also linked with the England international. In addition, Bolton also see the player as an ideal replacement for Gary Cahill who has been linked with Arsenal.