Spanish outlet Fichajes (h/t the Telegraph) claimed Ramires could move to Germany, as the player is currently "unsettled" at Stamford Bridge, but the Telegraph added Gundogan might be used as a makeweight in the deal.
Ramires has lost his place to John Obi Mikel since the arrival of interim manager Guus Hiddink, and his disappointment could thrust him into the arms of BVB.
Gundogan has previously been one of the most prized midfielders in Europe, impressing at the heart of the German national side.
German publication Bild (via Turkish outlet Bola, h/t Turkish Football) recently quoted Dortmund sporting director Michael Zorc saying the club are yet to open fresh contract negotiations with Gundogan, but he remains one of BVB's top priorities.
“Ilkay is one of our key players," said Zorc. "We’ll talk with him in due time on the future, but we still have a little time. If it was up to me, I would always insist only on long-term contracts. But then, Ilkay Gundogan would possibly for years no longer play here."
The midfielder has also been linked with a potential switch to Liverpool, with former BVB coach Jurgen Klopp taking the reins at Anfield, per Turkish Football. Gundogan spoke favourably about the Reds to Bild, saying, "They have a good team, a great coach."
However, a move to the Bridge would surely entice the Germany international, as Chelsea looked to rebuild after the failure of Jose Mourinho's second tenure as coach.
Here is a video displaying what Gundogan would bring to west London:
As the Blues consider their options, rumours have emerged Diego Costa may fly the nest shortly and return to Atletico Madrid during the current transfer window.
If Costa desires a move back to the Calderon Stadium, his intentions would be scuppered in the summer, if the Rojiblancos' punishment is upheld.
Costa has found his form under Hiddink since the departure of the self-proclaimed Special One, scoring five in his last five games, per Miller. The Blues snatched a 3-3 draw deep into stoppage time against Everton in the league on Saturday—with Costa adding to his tally—but journalist Piers Morgan speculated the champions are now in a dogfight:
Gundogan is a player of class and precision, but his addition at the Bridge would mean a change of style from Chelsea. The German will not want to sit on the bench at any prospective new club, and Chelsea would have to restructure their midfield to make space for his talent.
The German is more likely to replace Cesc Fabregas if he arrives, with Gundogan offering a box-to-box presence that Fabregas struggles to fulfil.
Costa looks lively once again in a Chelsea shirt, and with the lack of strikers available for the champions, it is hugely unlikely they will sell in the next few weeks.
The Brazilian-born ace is a vital member of the squad when happy and scoring, and his departure simply will not be considered at present by Hiddink.