The 22-year-old was one of the revelations of the 2013-14 season and played a key role in their La Liga title and their successful Champions League campaign, thus attracting the interest of a number of bigger clubs, including Barcelona.
Nevertheless, Koke has a contract with Atletico until the summer of 2018 and the Spanish champions will not let go of the midfielder on the cheap.
"Koke is an absolutely spectacular player," Bartomeu was quoted as saying by El Mundo Deportivo.
"He has had a great season and every club would love to have him.
"But I am sure that Atletico will want to hold on to him after such a great season."
Bartomeu also had his say on the future of Javier Mascherano and Xavi at Barcelona and insisted that the duo will not be going anywhere.
"Mascherano is a key player for Barcelona and will continue his career at Camp Nou.
"Xavi has a contract until 2016 and has two more years to go here. The coach counts on him for the future. He has been with the team for 16 years."