Wiese pulled on a Bremen shirt in a testimonial match for Torsten Frings last weekend but, in spite of the fans' calls for him to return to the Weser Stadion, Bremen coach Robin Dutt and director of sport Thomas Eichin said they are happy enough with Mielitz.
"Miele is our number one and he has our full support," said Eichin on the eve of Bremen's clash with Eintracht Frankfurt.
"That is a clear statement and everything else does not even play a role."
Wiese has been marginalised by his current club Hoffenheim, training with a small group of players who no longer have a future there.
Although the transfer window is closed, the former Germany international could theoretically return to Bremen by releasing himself from his Hoffenheim contract, but Eichin insists the north German club are not in the market for a new keeper.
"If we were, we had the chance during the transfer window to get one," he added at a press conference.
"We believe in Sebastian Mielitz and we never said anything differently. Tim Wiese will not be coming here, and with that, I would like the issue to be put behind us."
Full focus should instead be on the Frankfurt game and Dutt says Werder fans can play their part by showing their support for the goalkeeper who conceded four in Monchengladbach a fortnight ago.
"The fans here have a great feel for things and I hope, and am totally convinced that, they will demonstrate this towards Miele tomorrow," Dutt said.
"Our aim is to keep a clean sheet and to win against Frankfurt."
Frankfurt's aim is to come away from Bremen without any more injuries after losing a trio of regulars for Saturday's trip.
They start their Europa League campaign at Bordeaux on Thursday and need all the fit players they can muster.
"We'll manage to put together a decent side," said coach Armin Veh at a press conference. "This why we added numbers to our squad (this summer)."
Alexander Meier and Pirmin Schwegler are definitely out while Veh says he does not want to risk fellow a third midfielder, Johannes Flum, who is struggling with injury.