Marc Bartra hopes Pierre-Emerick Aubameyang rejects reported offers from China and England to stay at Borussia Dortmund.
Liverpool and Chelsea are said to be competing for the Gabon international's signing, with Chinese side Tianjin Quanjian reportedly considering an €80 million offer before their transfer window closes.
But Dortmund are hopeful of holding onto last season's Bundesliga top scorer and Bartra feels doing so will be pivotal to their 2017-18 campaign.
"Of course I hope Aubameyang stays," he told Bild. "He is important not only for his goals, but also for the spirit of the team."
The Spanish defender is optmistic about the future with BVB, having been convinced by new coach Peter Bosz and his philosophy after joining from Ajax as Thomas Tuchel's replacement.
"The first impression is really good. I also like his philosophy very well," he said of the Dutchman.
"When you look at his past, you can look forward to attractive football. It's a playing style that comes from Ajax, who have the same philosophy as Barcelona, both of which are coined by Johan Cruyff, which means that you want to control the game and have as much possession as possible.
"That makes me feel very comfortable."
After winning the DFB-Pokal, Bartra enjoyed his wedding with new wife Melissa Jimenez and is happy with his settled life, despite reports of interest from Manchester United.
"After the DFB-Pokal victory and the party in Berlin, then the wedding in Spain, it was the best summer of my life.
"I have experienced so much in this one year. It's like a family to me. That other clubs are interested in me shows that I am doing well. I'm pleased with the recognition I've received. But I think we will celebrate many wonderful experiences together in Dortmund."