The Spain international has led his side's title challenge this season, scoring 26 goals in 31 games in La Liga, prompting the Blues to take initial steps towards arranging a summer move for the player, as exclusively revealed by Goal.
Jose Mourinho has been repeatedly critical of his strikers this season and Simeone says that it is no surprise to see the Portuguese turn his attention to the Atleti hero.
|9/2||Atletico Madrid are 9/2 with Bet365 to beat Chelsea 1-0 in the first leg of their Champions League semi-final|
"It's normal that Chelsea are interested in him. They are an economic power, Samuel Eto'o is getting older and Costa can do his work, but right now he's ours."
Costa picked up an injury while scoring in his side's derby win over Getafe but Simeone insists that he is not overly concerned.
"It's not worrying me," he remarked. "Gabi came and told me that he had a cut. He risked his leg but he's like a bull. Costa, with that gesture, exemplied how we want to play every game as though it's our last."
The Argentine also touted his star striker as a potential Ballon d'Or winner if he continues to go from strength to strength.
Simeone enthused: "He has room for improvement. He's rebellious and I like that and he's something different. Hopefully his development won't end. Right now he's among the candidates for the Ballon d'Or."
Atleti are set to play Chelsea in the Champions League semi-finals and Simeone insists that Thibaut Courtois, who is on loan at the Estadio Vicente Calderon from Stamford Bridge, will be able to play - although he admits that the goalkeeper's long-term future remains less clear.
"I have no doubts that he will be able to play against Chelsea," he continued. "He also has no doubts. It's not a concern. I don't know where he'll play next season, though."