Although Arsenal has made some checks about Madueke's situation at Chelsea, this is not a unique approach. The club has done similar research on many other players. It is unclear at this time whether Madueke will be put up for sale by Chelsea.
Some rival clubs believe that Madueke could be made available as he is not considered a priority signing. Newcastle and Tottenham are also interested in the winger, who can play on both sides of the pitch.
It is worth noting that neither Arsenal nor Chelsea has made any official statements about Madueke's future. The transfer window is still several months away, and much can change between now and then.