Manchester United manager Alex Ferguson has given his clearest indication yet he would like to bring in some new faces to his squad.
With the opportunity to add players during January's transfer window fast approaching, Ferguson believes he may have to dip into the market to stay in touch with rivals Arsenal and Liverpool.
"We have created three teams in 10 years here, and it is possible we are on the way to building another one," Ferguson said.
"And if we do, obviously new players can come in. We have trusted and believed in the nucleus of our squad, which has been there for a long time.
"We always try to improve, and we have done that each summer, or we try to sign at least one player. Maybe it is time to assess that the nucleus of the team has been together for seven to nine years - it's a long time."
United have been off the pace in the Premiership this season, although they closed the gap to leaders Arsenal to six points with last week's win over Newcastle, and began the second stage of the Champions League with a 3-1 win in Basle.
Ferguson believes other teams have improved drastically while his Old Trafford side are not living up to their potential.
"I think Arsenal and Liverpool have improved and I don't think we are meeting our expectations at this moment in time," he added on the club's official website, www.manutd.com.