A mailman is replacing a hitman on ABC's "Dancing With the Stars."

John Ratzenberger, who played Cliff Claven on "Cheers," will step in for Vincent Pastore, who quit after one week of training.

Ratzenberger, 59, had previously turned down an offer to join the cast for the 10-week dance competition because of a scheduling conflict, ABC said Friday.

The 60-year-old Pastore, who played a tough-guy mobster on HBO's "The Sopranos," said earlier this week he didn't realize how physically demanding the show would be for him.

"We're sad that Vincent felt he was unable to continue in the competition, as he would have been great on the show," executive producer Conrad Green said in a statement Friday. "`Dancing With the Stars' is physically demanding, and it pays to know your limits. We respect his decision."

The new cast also includes Olympic skater Apolo Anton Ohno, boxer Laila Ali, former 'N Sync member Joey Fatone, country singer-actor Billy Ray Cyrus and Paul McCartney's estranged wife, Heather Mills.

"Dancing With the Stars" returns March 19.