Kevin Kuranyi claims Schalke's recruitment policy over the summer suggests they are content with being second best.
The Gelsenkirchen giants finished runners-up in the Bundesliga last season but have since lost two key players in Lincoln and Hamit Altintop.
Ivan Rakitic has been brought in from Basle for £3.4million while Jermaine Jones, Heiko Westermann and Mathias Schober complete the list of low-profile newcomers.
Kuranyi is not impressed.
He said: "I want to win titles. With the new signings made so far, the club is running the risk of always being second best - and I cannot be bothered with that any more.
"We are not only playing in the Champions League, but we also want to get in there again.
"Lincoln and Hamit have gone and their qualities have not been replaced.
"If nothing happens here, then we are facing a really tough season. The young players may be good, but the mix is not right."
The Germany striker is planning to air his feelings to the club in a bid to persuade them to take another scout around the transfer market.
"As soon as our general manager Andreas Muller is back from his holidays, I will discuss the problems," he told the Bild newspaper.
"I have already agreed that with Marcelo Bordon. I expect him to back me up."