Ivica Olic looks to be on his way back to Hamburg, with Andre Schurrle increasingly likely to join Wolfsburg.
St Johnstone boss Steve Lomas claims he may have to recruit a whole new team for next season.
The Northern Irishman is preparing for a busy summer after resigning himself to losing several of his key players.
Captain Jody Morris' future at McDiarmid Park is unresolved and top scorer Francisco Sandaza is also out of contract at the end of the current campaign.
And while Lomas expected his side's top-half finish in the Clydesdale Bank Premier League to attract the attention of other clubs, the turnover of players could be quite dramatic.
"You'd never like to have to bring in 10-13 players but that's something that looks like it is going to happen," the former Manchester City and West Ham midfielder told STV.
"It's going to be a really busy summer for myself and the chairman.
"Jody is probably looking to head back down to England, we've got the situation with Fran [Sandaza], Cillian [Sheridan, loan striker] who has still got another year in Bulgaria and Chris Millar has decided not to sign another contract, so yeah, there's a lot of issues.
"It's obviously disappointing that we haven't been able to sign the ones that we want but that's football.
"The lads have given great service to St Johnstone and hopefully they get a great send off."
Lomas was philosophical over midfielder Millar's decision to reject a two-year deal.
He said: "At the end of the day he's out of contract, he is free to explore other avenues, that's his obligation.
"We felt we offered him a really good deal in the present climate, to get a two-year contract is a very good offer.
"We're disappointed but that's football and we'll move on."
Millar is considering a move to Australia.
The 29-year-old, who has been with Saints for four seasons, has turned to a couple of former Perth players for advice on a potential move Down Under.
He told Saints' official website: "I've spoken to Simon Miotto and Mark Robertson who are both from Australia, they have both said it would be a great move for me and the family and I am keen to experience the lifestyle out there.
"I dare say some people will think that I am silly to refuse the offer of a two-year deal and time will tell if it is a good or bad decision although I have to stress that I have not shut the door on Saints completely."
Morris also tweeted that he was not certain to depart.
"For the record, I haven't agreed a deal nor have I turned a deal down from anybody," he said. "My future is not sorted yet."