Ipswich Town boss Roy Keane has threatened to let several of his underperforming reserve team players leave Portman Road in the summer unless their performances improve.Keane was left disappointed after watching Town reserves lose 2-1 to Luton Town in a Combination fixture at Playford Road on Tuesday, a match in which Bermuda’s Reggie Lambe was substituted after 72 minutes.Although Lambe was not named specifically as one of the underachievers, the 19-year-old Bermuda international is one of 21 players whose contracts expire at the end of the season.“It was very disappointing,” Keane, told the Ipswich Evening Star.“A number are due a reality check over the next few months particularly those whose contracts run out at the end of the season.“They have a lot to do if they want to be footballers at any level.“We rewarded seven scholars with one-year contracts at the end of last season, but they have not come on.“I told them that they would be in the big league now and they would not have academy manager Sammy Morgan and coach Gerard Nash putting their arms around them any more.“They are in the big world now they’ve got to earn themselves a living.“Jack Ainsley has gone on loan to Blue Square Premier Histon and he’s already had a reality check.“It’ll be an interesting few months for a number of players there is no problem with effort, but you’ve got to win football matches and when you get in a winning position see it through.”Keane exonerated youngsters Colin Healy and Ronan Murray from blame and they could feature at Preston today with Mark Kennedy having an outside chance of flying up with the squad.“We have sorted out Mark’s back problem that has not helped his run on hamstring problems, but we do not want to rush him however important his experience is to the team,” added Keane.Lambe, who started in Town’s 1-0 victory over West Bromwich Albion in the Carling Cup last week, has made four first team appearances this season.He was one of six youngsters handed contract extensions in May after scoring eight goals for Town’s reserve team last term.