Sporting Lisbon are reportedly wary of Manchester City making an attempt to re-sign defender Pedro Porro.
Despite a season of mixed fortunes, Porro has emerged as one of Sporting's most valuable players, contributing two goals and seven assists in Primeira Liga and Champions League fixtures.
However, the form of the wing-back has lead to strong interest from elsewhere with Tottenham Hotspur known to be attempting to sign the 23-year-old.
While negotiations are said to be ongoing, Sporting have been reluctant to part ways with Porro for anything less than his £39m release clause.
As it stands, according to transfer expert Fabrizio Romano, discussions are reaching a crucial period and should progress over the coming days.
Although the Portuguese giants are expected to retain a strong stance, they also have to take into account other factors, including Porro's former club Manchester City.
The Spaniard did not play a single fixture for the Premier League giants during his three years contracted to the club, instead spending loan spells at Real Valladolid and Sporting.
Nevertheless, when Sporting were able to sign Porro for £7.2m last summer, it came with City inserting a buy-back clause which is allegedly set in the region of €20m (£17.65m).
According to 90min, Sporting have concerns that City will eventually want to activate that option if they do not cash in on Porro beforehand.
Head coach Ruben Amorim has previously stated that it would take a bid which matches Porro's release clause, almost double that of City's buy-back clause, for a sale to be concluded in January.
However, Sporting officials seemingly fee that it is realistic that Porro could be regarded as a player who would offer considerable value for money to City.
Pep Guardiola currently has three right-backs at his disposal in the form of Kyle Walker, Joao Cancelo and Rico Lewis, but the long-term futures of the former duo are uncertain.
Walker turns 33 years of age in May and has injury issues, while Cancelo has recently been linked with an exit after teenager Lewis moved ahead of him in the pecking order. body check tags ::