Initial talks have already been held between the two parties.
Werder Bremen sporting director Clemens Fritz is keen to avoid a repeat of last year's chaotic late transfer window and wants any new arrival "available from day one."
Cuello, 26, has scored 20 goals in 99 appearances for CA San Lorenzo since joining in January 2025 for a fee of around €1 million, and his contract situation works in Bremen's favour, with the deal in Argentina running only until December 2027, keeping any transfer fee within a manageable range.
Competition for the forward is significant, however. Hertha BSC have also made contact, while Serie A side AC Monza, Argentina's Talleres and Mexico's Monterrey are all credited with interest, a level of competition that could drive the eventual fee upward.
The 1.86m Cuello's finishing form has been inconsistent by his own admission — his best return in a single season stands at five goals — something Bremen will need to weigh given they have already added forwards Cedric Itten and Kenny Quetant this summer, with Salim Musah also expected to take on a bigger role in attack.
Bremen open their season with a Pokal first-round tie against Hansa Lüneburg on August 22, giving the club roughly three weeks to complete the bulk of their remaining transfer business, with the club's focus continuing to centre on strengthening the centre-forward position above all else.
Bremen had previously been credited with interest in Willem Geubbels and Noel Futkeu as alternative striker options before turning their attention to Cuello, who is understood to be valued in the region of €5m by Transfermarkt, some way below the €6m release clause reportedly attached to his contract that emerged during earlier talks between San Lorenzo and Brazilian club Fluminense.
The Argentine, a right-footed centre-forward primarily but capable of playing off the left, has scored six goals and provided five assists in the current Argentine league season, numbers that suggest an uptick in form compared with his previous campaigns at the club.