According to Sky Germany, Newcastle United are "specifically interested" in the Poland international, while Bayer Leverkusen have already held initial meetings with the player's representatives — a development that suggests the Bundesliga side have moved first.
Potulski made 23 appearances for Mainz this season, including eight in the UEFA Conference League. He broke into the side in the second half of the campaign and impressed sufficiently to earn his first two senior Poland caps, scoring in a 2-2 friendly against Nigeria.
He joined Mainz from Legia Warsaw as a free agent in the summer of 2023 at the age of 15. His rise through the club's academy and into first-team football has been rapid.
A transfer will not come cheaply. Mainz have Potulski under contract until 2028, giving them full control of any negotiation. Polish outlet goal.pl reports the club value him at above the €18 million figure cited by Transfermarkt. Earlier this year, Borussia Dortmund were understood to be willing to pay up to €25 million — and still could not agree terms. Mainz are not in a hurry.
Potulski's decision to recently change agents is a significant detail. In football, that step typically signals that a player is preparing for a move and wants representation capable of handling a high-profile transfer.
Newcastle's interest reflects the club's established approach to the German market. The Magpies have consistently looked to Bundesliga and 2. Bundesliga talent as a source of quality at value. A centre-back with Potulski's profile — left-footed, composed, capable of playing at European level as a teenager — fits the template precisely.
Whether the pull of remaining in Germany will prove stronger than a move to the Premier League is not yet clear. Leverkusen can offer Champions League football next season; Newcastle can offer the Premier League and the prospect of European competition in the future.
Mainz are in no rush. The clubs will have to make them move.