"Rushing ahead on your own, whether at diocesan or national level" is not expedient, writes Tück on the theological portal "communio.de" (Saturday), for which he is responsible.
Overbeck announced on Thursday that a"Joint Council" made up of clergy and laity would begin its work in the Ruhr diocese in April.
The new, synodal body with 21 voting members from other committees and groups in the diocese will advise the bishop on fundamental issues.
Tück pointed out that the Vatican had repeatedly emphasised that the Synodal Way reform project in Germany was "not authorised to oblige the bishops and the faithful to adopt new forms of leadership and new orientations in doctrine and morals".
In addition, there is the instruction "that neither the Synodal Way nor a body appointed by it nor a bishops' conference have the authority to establish the 'Synodal Council' at national, diocesan or parish level".
Blank space from Rome
Tück added that the Vatican had not explicitly named the local bishop and the diocese: "Is the blank space intentionally left by Rome? Or is the intention in Essen to exploit the gap in the statement in an insubordinate manner - according to the motto: what is forbidden to the Synodal Way or the Bishops' Conference must be permitted to the bishop of a diocese?"
According to Tück, it is also striking that the new body in Essen is not called the "Synodal Council", but the "Common Council": "Do they believe that the trick of such a renaming means they will no longer be hit by the series of Roman objections?"
The majority of bishops in Germany have announced their intention to voluntarily bind themselves to the votes of mixed synodal councils.
However, conflicts of loyalty with the bishop's obedience to the Pope are almost inevitable, added Tück.
A "salutary decentralisation" could thus lead to "hopeless fragmentation if it becomes common practice for bishops to disregard the Pope's explicit votes".
Tück criticises the fact that Overbeck wants to create facts with the new committee before the synodal process of the universal church ends with the second phase in October: "The promotion of a synodal culture of participation in Germany will not progress against Rome, but only with it."