The Whites legends is desperate to see the club do well.
Steve Evans's side are bang in form, beating Blackburn Rovers 2-1 at Ewood Park on Saturday for their third successive victory since the demoralising 4-0 defeat at Brighton & Hove Albion 12 days ago.
Unfortunately for Leeds, their form earlier in the campaign put paid to any hopes of reaching the playoffs, with United 12 points behind Sheffield Wednesday in sixth.
There is always next year though, but former Whites striker Whelan says that their promotion hopes next term hinge on a successful recruitment drive during the off season.
"Away from home, that first goal gives you a boost of confidence and it is normally the decider," he said on BBC.
"They're going out there now with confidence and we have trust in the players.
"It's important over the summer that we buy right and give ourselves the best chance of competing."
Evans said recently that his aim this season was to secure a top-10 finish, which looks an achievable goal as Leeds sit five points behind Preston North End, who have played one game more than them.
Should they finish in the top half, it would represent real progress after the ex-Rotherham United boss was told to avoid relegation when he replaced Uwe Rosler in October.