Leeds boss Simon Grayson has vowed his team will be a more potent force for the start of next season.
The players trained for the final time before the summer on Monday after Thursday's play-off defeat by Millwall.
Grayson told the club website: "They are still hugely disappointed with how it ended - so close yet so far away.
"We had a chat on Monday morning, and we have to use the disappointment as an inspiration to come back fit and strong and ready to go."
"It's disappointing for the players and the staff but more so for the fans because they have been outstanding.
"The players are down. We had a good chat about what we've done, what we achieved, and what we expect next year.
"Now they have to get it out of their system and report back and, all it's systems go. We'll have a good pre-season and get ready."
It was the third time in four years that Leeds missed out in the play-offs, and Grayson's squad can expect a rigorous pre-season programme as they aim for automatic promotion.
"The days have gone when pre-season is all about running around Roundhay Park, and there will be a lot with the ball," he said.
"We want to be the fittest and strongest in the league, and that will be the case.
"We can't have any hangovers now. I don't expect the players to forget about it immediately.
"They'll be reminded in a week's time when the play-off finals are on TV and when the fixtures come out. But we can't live in the past.
"I've no complaints with what they've contributed since I came here, but that's gone. We have to forget about the play-offs and concentrate on automatic promotion."