Maguire, who famously struck for his boss Donald McCain on Ballabriggs in 2011, suffered a fall at Catterick, with resultant news from scans suggesting he may be on the sidelines for the world’s greatest steeplechase for the second successive year.
The news adds further to a “frustrating” season for Maguire, who was forced to miss the Cheltenham Festival through suspension.
Writing in his blog on lovetheraces.com, Maguire said: “My frustrating season continues. After missing the Cheltenham Festival with a lengthy ban, my misery was compounded further by the fact I managed to pick up quite a bad injury when falling at Catterick last month.
“The first scan I had after the fall suggested that I had a slipped disc and I may have damaged one of my vertebrae, which is not good news at all. I’m having a second opinion on it next week, but the initial signs are not good, which means I may be ruled out of riding in the Grand National for the second year running.
“It’s fair to say luck is not on my side at the minute.”
Maguire missed Cheltenham and Aintree 12 months ago when a bad fall on the eve of the Festival left him with serious injuries in hospital.
Meanwhil e Rodger Sweeney believes the journey to Cheltenham left a mark on Salsify this time around after he disappointed when chasing a hat-trick in last week’s Foxhunter Chase.
The 10-year-old claimed the famous prize in 2012 and 2013, but missed the following year’s renewal due to injury.
He returned from over a year off with a creditable effort at Leopardstown last month, but was pulled up by the trainer’s son Colman on his return to Prestbury Park.
Sweeney said: “He came back all right. He didn’t travel that well this year, unfortunately.
“These things happen and there’s nothing you can do about it.
“We’ll see how he is. If he’s ready for Punchestown, we’ll aim for that.”
Carsonstown Boy is on course to run at Fairyhouse’s Easter meeting following another fine effort at Cheltenham.
Trainer Colin McBratney is targeting the Joseph O’Reilly Memorial Hunters’ Chase for the 11-year-old after he ran with credit in the Foxhunter Chase for the second successive season.
Second in 2014, Carsonstown Boy was fourth to On the Fringe in the latest renewal.
“He’s come out of the race in good form, so we’ll probably go for the Joseph O’Reilly at Easter in Fairyhouse,” said the County Down handler.
“He’ll have an easy week, see how we go and start him again next week.”
Pat Cosgrave is to miss the start of the of the Flat season after fracturing his leg following an incident on the gallops on Wednesday.
The 32-year-old sustained a broken fibula above his right ankle while riding work for George Baker, after a horse slipped and fell on him while walking back.