The comments came days after paceman Mohammad Amir looked set to return to the Pakistan team after being selected for an upcoming series in New Zealand, months after completing a five-year spot-fixing ban.
"I will welcome not only Amir but whosoever has completed
A sentence," Younis told AFP.
"If they (Butt and Asif) have (completed their sentences) and are eligible then, of course, selectors should keep an eye on them," he said.
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The scandal also involved Butt and fellow bowler Asif, who are now undergoing rehabilitation and will feature in a national one-day tournament starting from January 10.
"I don't know how long they will take to prove themselves fit and ready to go, one year or six months, whenever they are ready they should be given another opportunity," said Younis.
Amir's return to the squad was opposed by one-day captain Azhar Ali and former Twenty20 captain and current player Mohammad Hafeez.
Last week Mohammad Hafeez and Azhar Ali left a training camp Amir was attending in protest at his prospective selection. They were later forced to return after being threatened with disciplinary action.
Ali also tendered his resignation Monday in protest, but it was rejected by Pakistan Cricket Board.
Pakistan fly to New Zealand on January 10.