Nina Carberry is to ride the Tom Hogan-trained Shannon Spirit in the Weatherbys Champion Bumper.
Carberry, who is already the most successful female jockey at the Cheltenham Festival, has only just returned to action after five weeks out with a broken toe.
Shannon Spirit, who is one of 38 entries for an extremely popular betting event, was ridden by Pauline Ryan on his only outing so far when scoring by seven lengths at Thurles in mid-January.
"A lot of professionals have approached me for the ride, but amateurs have a good record in the race and Nina was interested before the horse first ran," Hogan explained. "She was committed elsewhere on the day he ran but she has been down for him for a few weeks.
"We've been looking at this for quite a while. He's a nice horse and hopefully he would have a chance as it's an open race."
Oscar dies after Ulster triumph
There was a sad postscript to the Toals Bookmakers Ulster Grand National at Downpatrick as Chief Oscar suffered a heart attack after passing the post in front.
Trained locally by Brian Hamilton, the 16/1 chance was disputing the lead a long way from home and produced a couple of fine leaps at the final two fences to hold a clear advantage turning for home.
He answered Andrew Lynch's every call on the run-in to win by a neck from Bally Wall. But the nine-year-old stumbled to the ground as Lynch was pulling up and did not rise to his feet.
Hamilton said: "He collapsed past the line, the vet said he probably ruptured an artery and had a heart attack.
"He's just such an honest horse and he gave his all. He has won three times around here, it's just such a horrible thing to happen."
Taranis pulled out of big days
Taranis will not run in the totesport Cheltenham Gold Cup or the John Smith's Grand National.
Paul Nicholls' nine-year-old has met with a setback and has been scratched from the two feature events of the National Hunt season, according to official notices from Weatherbys.
Owner Angela Yeoman said: "It is not a leg problem, which is a relief, but something is the matter with him.
"We are not quite sure what the problem is yet, but I don't want to run him if he's not right.
"I knew there was a little problem on Tuesday night but I've not spoken to Paul today."