The two players, who were signed by Keane in his very first week at the club, looked to be on their way earlier this year when both were told they would be allowed to leave.
But Keane has revealed that both have now played their way back into his squad and will be given chances to prove themselves.
He said: "I've taken them off that.
"Ross has come back and looked pretty sharp, following on from how well he was doing towards the back end of last season.
"Liam has kept his head down like a good professional and been doing things properly and I take note of that. If you do that, there won't be an issue.
"Last year is history and you have to move on."
Both players were involved in well over half of Sunderland's games last season but Miller was transfer-listed for persistent lateness while Wallace also fell foul of the manager and was put on the list in the January transfer window.
Wallace then suffered a ligament injury which looked to rule him out for the rest of the season but as the campaign drew to a close, both had fought their way back into the first-team picture.
And Keane hopes they have both now learned their lessons.
He said: "It was never a case of me wanting them out the door.
"Sometimes players need a kick up the backsides to put them back on the right track and hopefully that's what's happened in this case.
"But it doesn't for one second suggest that I'll tolerate poor standards of behaviour in the future either."
Miller has not made the pre-season trip to Portugal after picking up a minor foot injury in training.
Other players remaining behind because of injury are Kenwyne Jones, Paul McShane, David Connolly and Dickson Etuhu.
Keane has taken a 21-man squad to Albufiera, comprising three goalkeepers, five defenders, eight midfielders and five strikers.
The squad is: Gordon, Fulop, Ward, Bardsley, Nosworthy, Anderson, Higginbotham, Collins, Edwards, Whitehead, Yorke, Richardson, Reid, Leadbitter, Kavanagh, Wallace, Murphy, Stokes, Prica, O'Donovan, Chopra.