In Val's latest article he mentions these two players as possibly joining Adelaide.
Merkel is a particularly interesting prospect, only 25 years old but he debuted and started for AC MIlan as an 18 year back in 2011 when it looked like he was going to be a star. He has clearly fallen well short of those early expectations but still could be an excellent A-league CM/AM. He could fit in beside Isaias in a 4-2-3-1 or more likely as the AM in the same formation. 
Avaridis is an experienced winger/striker who could fit onto the RW or even AM in behind Baba. 

Also Carrusca is said to be signing for another club, Melbourne City, or making Brisbane even older?

http://www.adelaidenow.com.au/sport/football/a-league/teams/adelaide/adelaide-united-tracking-two-more-foreigners-for-the-new-season/news-story/92e7d54eaca92eb119b8fe30acc76a74

Vince Lia is trialling with Adelaide.

Why would Lia have to trial? Hes a pretty known commodity at this level.

Vinnie lia Isnt as bad as people think, top bloke too.

A foreign coach who probably has never seen him play. Elsey and Marino who were at the club last year are also being asked to trail as well.

Any progress on either of these two?