Aberdeen have signed former Cardiff striker Josh Magennis and have ex-Leeds United keeper Ryan Jones and ex-West Ham midfielder Conor Okus on trial.
Northern Irishman Magennis, 19, will add to the youthful spirit at Pittodrie as the 18-year-old trialists joined the Dons in pre-season training on Monday.
A product of Liverpool's academy, Jones moved on to Wigan before joining Leeds, where he was on the bench last season.
And Okus was part of the Hammers' youth team last term.
Magennis, who switched to being a striker after an early career in goals, scored twice for the Northern Ireland Under-21s against Iceland in 2009 and made his full debut against Turkey in a friendly in May.
We hope to give them an opportunity and to improve them and benefit from that
Mark McGhee on the policy of inviting youth academy players for trial
Also joining Aberdeen for pre-season was Rory McArdle, the Northern Ireland defender who signed for the Scottish Premier League club this summer after leaving Rochdale.
Manager Mark McGhee said: "There will be half a dozen more trialists for pre-season training that we will have a look at, who may or may not join us on our pre-season tour.
"Conor Okus is a young player who has come from a club who have a great record of producing good footballers.
"They come with a good mentality and a good upbringing, as it were. We have to try to take advantage of other people's mistakes.
Magennis played as a goalkeeper for Northern Ireland Under-17s
"We hope to give them an opportunity and to improve them and benefit from that."
However, manager Mark McGhee is looking to further bolster his squad after several players departed Pittodrie.
Captain Mark Kerr will look to feature in Asteras Tripolis' midfield in Greek's top flight, wing-back Charlie Mulgrew joined Celtic, defender Davide Grassi opted for a return to Italy to join Sorrento Calcio, while striker Steven MacLean went back to Plymouth Argyle at the end of his loan.
Goalkeeper Stuart Nelson joined Notts County and another fringe player, winger Paul Marshall, joined Walsall.
Meanwhile, midfielders Gary McDonald and Stuart Duff are looking for new clubs.
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