Tweets containing racist and homophobic language from five years ago have surfaced just two days after White Sox pitcher’s Michael Kopech’s major-league debut, according to a local newspaper.

The White Sox did not respond to NBC 5’s request for comment and the tweets have since been deleted—though screenshots remain. Kopech told the Chicago Sun-Times he deleted the posts and called them “immature and inappropriate.”

“I used some poor language in there,” the newspaper reported Kopech as saying. “Obviously, I’m trying to be looked at as a role model and the last thing I want to do is have some kid look at what I’m saying and take it the wrong way.”

Kopech, who is 22 years old, was 17 at the time he posted the messages.

Comments made by Chicago Cubs infielder Daniel Murphy in the past about homosexuality caused controversy among some fans when he was acquired earlier this week.