A spokeswoman for the Cook County Medical Examiner confirmed her office was investigating the death.

The Chicago Cubs were scheduled to play the Cardinals on Saturday afternoon at Chicago's Wrigley Field, but the baseball game was cancelled following reports that the veteran pitcher had been found dead.

"We got a call that he had expired. Our doctor won't examine the body until tomorrow. We can't confirm anything. We haven't investigated the scene," the spokeswoman at the medical examiner's office said.

She said her office was called to the Westin Hotel at 909 N. Michigan Avenue in Chicago's Gold Coast neighbourhood on Saturday afternoon.

No further details were immediately available about the cause of death.

"Our guess, passed on to me, was that he died in his sleep," Cardinals manager Tony La Russa said.

"That's what was told to me."

He leaves behind a wife Flynn, and twins, son Kannon and daughter Sierra and a son born last summer.

Kile, who was 16-11 with a 3.09 ERA and threw 227 1-3 innings last year, had arthroscopic surgery on his right shoulder during the off-season.

He pitched a no-hitter while with Houston in 1993 against the New York Mets. He was 133-119 in 11-plus major league seasons and known for an exceptional curveball.

Kile's best season was 2000, when he went 20-9 with a 3.91 ERA in his first year with St. Louis - finishing fifth in NL Cy Young voting.

He also helped St Louis advance to the NL championship series against the Mets that season.

Kile was traded to St Louis from Colorado, along with pitchers Dave Veres and Luther Hackman on 16 November 1999, for pitchers Jose Jimenez, Manny Aybar and Rick Croushore and infielder Brent Butler.

A 30th-round pick of the Astros in 1987, Kile was called up to the majors in 1991 and went 7-11.

He spent his first seven major league seasons with Houston, finishing fifth in NL Cy Young voting in 1997 after going 19-7 with a 2.57 ERA.

Kile signed with Colorado during the offseason and struggled in his two seasons with the Rockies.

He led the league in losses with 17 in 1998 and was 21-30 with Colorado.