Our sources tell us Mark canceled Monday's rehearsal because of a party for his mother. But Bristol canceled Tuesday because she had committed to giving a speech. And Bristol canceled Wednesday because her son, Tripp, was ill. And she was only able to practice a half day on Thursday.
Some members of the cast tell us ... Mark is worried the newbie just won't cut it when the show premieres a week from Monday.
But there's another side to this story ... sources connected with the show tell us Mark was really happy with Bristol's progress on Friday and they will be practicing the entire weekend and every day next week until the first live TV show.
On the bright side, if Bristol falls flat, she could get appointed to some position in Wasilla.