Edouard Mendy has reportedly agreed a five-year contract with Chelsea ahead of a proposed move to Stamford Bridge during this summer's transfer window.
Holveck, though, was keen to stress that an agreement between all three parties had yet to be reached.
According to RMC Sport, Mendy has agreed personal terms on a five-year deal with Frank Lampard's side, who have been extremely active during the current transfer window.
However, the report claims that the Premier League giants are still €8m (£7.4m) short of Rennes's €28m (£25.9m) valuation.
The Blues broke the transfer record for a goalkeeper when they signed Kepa Arrizabalaga from Athletic Bilbao in 2018, but the Spain international has struggled to make his mark in London.