Costa has not scored in his past six outings for the Blues and was in hot water after raising an arm to Stoke defender Ryan Shawcross on Saturday.
Wright said: "He seems a little bit more antagonizing. The first season he got here he was focusing on scoring goals, being in the box. Now he's outside the box, he's getting involved with people.
"I believe at this moment now, he's the last centre forward you need. You need a centre forward who's going to get on with it, stretch teams and cause teams problems in the right way."