Chelsea have reportedly been told that it could take as much as £23m to secure the services of Barcelona striker Pierre-Emerick Aubameyang.
La Blaugrana did not pay Arsenal a penny to bring the 33-year-old to Camp Nou in January, with the Gunners terminating his contract after he was stripped of the captaincy.
Aubameyang struggled to return to his best form in his final 18 months at Arsenal, but he hit the ground running at Barcelona as Xavi's focal point.
The ex-Borussia Dortmund man ended his first half-season at the club with 13 goals from 23 games in all tournaments, including 11 strikes from 17 La Liga outings.
However, Aubameyang is now facing competition up top from old Bundesliga rival Robert Lewandowski, who was given the nod for the weekend's La Liga opener with Rayo Vallecano.
Aubameyang was only brought off the bench in the final eight minutes of the encounter, but he was powerless to prevent Xavi's side from being forced to accept a 0-0 draw.
Following Lewandowski's arrival, Chelsea have been tipped to bring Aubameyang back to the Premier League, and Barcelona are supposedly willing to do business with the Blues.
Thomas Tuchel will not reunite with Aubameyang on the cheap, though, as journalist Gerard Romero claims that Barcelona want at least £21m to part ways with the Gabon international.
Romero adds that Barcelona could even hold out for a fee closer to £23m, with Aubameyang still contracted to the Catalan giants for another three years.
Chelsea are said to have baulked at Barcelona's asking price, and Aubameyang is keen to fight for his place at Camp Nou, but the Blues are still discussing a possible move with the Blaugrana.
Aubameyang netted 68 goals and set up 16 more in 128 Premier League matches during his time with the Gunners and previously worked under Tuchel during his prolific spell at Dortmund.
Tuchel was asked about the speculation surrounding Aubameyang's future before Sunday's 2-2 draw with Tottenham Hotspur, and the German spoke about the striker still being one of 'his players', adding fuel to the fire over a potential transfer.
"I enjoyed a lot working with him, it was a pleasure. This has nothing to do with the situation now, but some players stay your players because you were very, very close and Auba is one of those players," Tuchel told reporters.
"We had a very close relationship. Always when he played here with Arsenal, it was straight away this close bond. They always stay your players in a way and Auba is one of those players."
Chelsea have already allowed Romelu Lukaku to return to Inter Milan on loan, while Timo Werner ended his two-year spell at the club with a permanent move back to RB Leipzig earlier this month.
Raheem Sterling has arrived from Manchester City to bolster the attacking ranks, and Chelsea are also rumoured to have seen a £40m bid for Everton attacker Anthony Gordon rejected.
