Unfortunately a brief email exchange has revealed that he will not be able to take advantage of this opportunity. Due to an impending shoulder injury requiring surgery and extensive recovery time and Johnson will not be entered in the 2015 Dakar.
He is however looking to the future in regards to the international exposure that the Dakar could bring both himself and his sponsors:
"My tire sponsor (Radar Tires) still really wants to do it so we may try to put a program together for 2016. I think it's a great thing what Roger Norman, SCORE and the Dakar guys are doing to get the two series together, it will only help strengthen each series both in outside interest (fans) as well as sponsors & TV worldwide."
One last item of note--the Dakar organizers do not allow you to carry over a free entry win from one year to the next so unfortunately Johnson will have to go back out and with the free entry again in '15 if he or Radar Tires or others are not going to pay for the entry fee out of pocket. Its a use it or lose it proposition. A shame really but likely an appropriate one designed to encourage entries to come to the event rather than just leave it out there as an idea to always hold in your back pocket for when the "time is right".
Thanks to Mike for the brief conservation and make a quick recovery!