Ron Edmonds / Invision/AP 1 / 4
Ron Edmonds / Invision/AP 1 / 4

CHICAGO -- Sarah Palin says it's "a bit heartbreaking" to see the road the father of her grandson has taken.

Palin appeared on Monday's episode of "The Oprah Winfrey Show," saying Levi Johnston is on a road that is "not a healthy place to be."

Palin's 413-page book, "Going Rogue," will be released Tuesday and she begins a book tour Wednesday in Grand Rapids, Mich.

The new memoir doesn't contain any references to Johnston, who's sparred with his former mother-in-law-to-be.

The former Alaska governor and former Republican vice presidential candidate told Winfrey that Johnston has been busy with media tours and hasn't seen his son "for a while."

Palin also says she continues "to hope for the best and to pray for Levi."