Updated

The deal for Mark Martin to replace Denny Hamlin apparently fell apart Friday, with Michael Waltrip Racing announcing Martin will only drive Hamlin's car at Martinsville.

The about-face comes roughly 24 hours after Joe Gibbs Racing said Martin would drive the No. 11 Toyota while Hamlin recovers from a fractured vertebra in his lower back. Hamlin is expected to miss at least five races.

Martin will now drive Hamlin's car only next week at Martinsville. He was scheduled to be off next weekend, with Brian Vickers slated to drive the No. 55 Toyota.

MWR said Martin will return to his regular car after Martinsville and "resume his previously scheduled run of events with MWR" for the rest of the season.

It's not clear who will drive Hamlin's car after Martinsville.