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Transfer speculation has dominated the headlines in Bremen this week, with the likelihood of the current squad falling apart in the summer increasing.

First, it was reported that Claudio Pizarro has activated an option in his contract which means it will now terminate at the end of June, 12 months earlier than planned, and then the future of defender Naldo became shrouded in doubt amid reports of a bid from Brazil.

With the deadline for transfers to Brazil this coming Wednesday, Naldo may not even end the season in Germany.

"I have heard of an offer," Naldo told the Bild newspaper. "There is not much time and I will have to speak with my agent to find out what is happening.

"It is possible that something still happens."

Gremio are reported to have made a bid for the 29-year-old, who was close to leaving the club in the winter before being told to stay.

With the contract of goalkeeper Tim Wiese also up for renewal, the Bremen team which takes to the field on Saturday may bear no resemblance to the one which lines up in the Bundesliga next season.

Already, coach Thomas Schaaf was forced to name his youngest-ever starting XI for last weekend's clash with Augsburg due to injuries and suspension.

Pizarro and Wiese should return tomorrow while Marko Marin could also be a candidate again.

Mainz coach Thomas Tuchel is particularly concerned about Pizarro's return after a two-game ban.

"We need to ensure we cut off the supply line to him," he said.

"He has a great record and is one of the best players in the Bundesliga.

"We are also going to need a bit of luck to deal with him."

Mainz managed it last season, though, when they won 2-0 in northern Germany and Tuchel says a similar result is possible.

"There are situations in which we can beat Werder," he said at the pre-match press conference.

"We need a top performance in all areas and we will have to be wide awake if we want to take anything from Bremen."

Tuchel has Jan Kirchhoff and Nikolce Noveski both available for selection after injury.