Aberdeen hope to retain on-loan Norwich City full-back Steven Smith after the end of the season but have told three players they will be released.
Fellow defender David McNamee, goalkeeper Mark Howard and the versatile Derek Young will not be offered new contracts.
And fellow loan players Nikola Vujadinovic and Nick Blackman will return to their clubs.
The Dons will hold talks with Norwich and hope to agree a deal over Smith.
Aberdeen have already been in negotiations with forwards Chris Maguire and Sone Aluko, plus goalkeeper Jamie Langfield, about new contracts to extend their stay at Pittodrie.
And manager Craig Brown hopes that Smith will join them, the former Rangers left-back having become a regular for the Dons since arriving on loan in January.
The 25-year-old joined Norwich last summer after leaving Ibrox and failed to settle during an injury-hit spell at Carrow Road.
With Paul Lambert's side lying second in the Championship and close to clinching a place in England's top flight, Smith is likely to be allowed to leave the Canaries should an agreement be reached with the Dons.
Meanwhile, Brown has praised 30-year-old Young, who started his second spell at Pittodrie in 2007 after spells with Dunfermline Athletic, St Johnstone and Partick Thistle.
"Derek's commitment and willingness to play in a variety of positions for the team made him an invaluable asset for us this season and it was a very hard decision for us to make," the manager told the Dons website.
"But, by allowing Derek to leave, it will enable us to free up space to recruit new players.
"It is in no way a reflection of his efforts for the club, which have been exemplary."
Injury-plagued McNamee, capped four times for Scotland, signed a short-term deal with the Dons in December after being released by Plymouth Argyle in the summer.
However, the former St Mirren, Blackburn Rovers, Livingston and Coventry City defender was restricted to 12 Dons games because of various knocks.
Former Arsenal and Cardiff City goalkeeper Howard moved to Pittodrie last summer after three years with Scottish Premier League rivals St Mirren, but the 24-year-old has made only nine appearances.
"Mark Howard understandably wants to play every week and he was clearly number two here, so he will now get the opportunity to play elsewhere," explained Brown.
"David McNamee has been bedevilled by injury during his time here, but he made a great contribution to the team short term when we were struggling at full back."
Blackman had started the season on loan with Motherwell and followed Brown in January after the manager switched from Fir Park to Pittodrie.
The 21-year-old had made a significant impact with Motherwell, scoring 10 times, but he managed only two with the Dons and has been mainly used as a substitute.
Vujadinovic - who has previously played for Rad Beograd, Zeta, Radnicki Pirot and CSKA Sofia - joined the Dons from Udinese on loan, but the 24-year-old Montenegrin has been an inconsistent performer in his 21 appearances, nearly half from the bench.
Aberdeen have also confirmed that defender Myles Anderson will be leaving Pittodrie.
Blackburn Rovers had already announced that the 20-year-old, who joined the Dons in January after being released by Leyton Orient but has played just once under Brown, had signed for the English Premier League outfit on a pre-contract agreement.