Replacing the irreplaceable - Tom O'Brien gets the call at Philip Hobbs's yard

Tom O'Brien, a mainstay of the Philip Hobbs yard over the past 15 years, looks likely to step into the considerable void left by the retirement of long-standing first jockey Richard Johnson on Saturday.

O'Brien was champion conditional with Hobbs's backing in 2006-07 and is just 22 winners away from riding 1,000 winners over jumps in Britain.

His notable wins for the yard include the 2009 Welsh Grand National on Dream Alliance and the Grade 2 1965 Chase at Ascot on Royal Regatta in 2016. He can potentially look forward to riding the likes of Grade 1 winners Thyme Hill and Sporting John for Hobbs.

Tom O'Brien won the Welsh Grand National on Dream Alliance for Philip Hobbs in 2009Credit: Julian Finney (Getty Images)

"Tom O'Brien will be riding the majority of them and we'll go from there," Hobbs told Luck On Sunday. "We also have Sean [Houlihan] and Ben [Jones] too, they're both 3lb claimers and they are involved here on a daily basis - they're very reliable, good, honest lads.

"I must also mention Micheal Nolan, who was second in the conditional jockeys' title some years ago and has been so unlucky with injuries, but hopefully he's getting over that now and rode a treble the other day at Wincanton. He'll have plenty of chances too."

Hobbs added: "Like Richard, Tom was champion conditional going back some years ago. He's a very good rider but hasn't had all the opportunities that he perhaps deserves. There will be more opportunities for him from now on."

Johnson's retirement has also left a vacancy aboard the Colin Tizzard-trained former Cheltenham Gold Cup winner Native River, although no decision on who will ride the 11-year-old has been made yet. He has an entry in the Grade 1 Betway Bowl at Aintree on Thursday.

A new jockey needs to be found for former Cheltenham Gold Cup winner Native RiverCredit: Edward Whitaker

"Jonjo O'Neill stood in for Dickie in the Denman Chase but we haven't really discussed it yet," said Native River's owner Garth Broom.

"We're deliberating whether to run at Aintree on Thursday because there isn't much forecast for rain. It's difficult to ask a rider to ride him when we don't know until the last minute if he'll run.

"We don't want to rattle him up on too firm a ground or anything as we may be able to run next autumn if he's well."

Having won the rearranged Cotswold Chase at Sandown in February, Native River finished fourth on his fourth crack at the Gold Cup last month.

Read more on Richard Johnson's retirement . . .

Richard Johnson: after 30 years the time has come to retire

'If Dickie has a bad word to say about you there's something wrong with you (Members' Club)

Richard Johnson's top ten rides from an illustrious jump racing career

Philip Hobbs: 'I have never, not once, had a fallout with Richard Johnson over anything'

A sport could not have had a finer role model or ambassador than Richard Johnson (Members' Club)

Tony McCoy tells Richard Johnson: look in the mirror and you will see a champion

'He always pretended to be a jockey, it's all he ever wanted to be' (Members Club)

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