Two of standout Irish trainer Aidan O’Brien’s star runners, Santa Barbara and St Mark’s Basilica, are both out indefinitely after suffering injuries.

St Mark's Basilica-Injured
Trainer Aidan O’Brien’s star colt St Mark’s Basilica is 6-for-9 in his career. He’s out indefinitely with an infected hind leg. (Image: Healy Racing)

Santa Barbara, who won the Grade 1 Belmont Oaks and Grade 1 Beverly D at Arlington Park, won’t head to the Breeders’ Cup Filly & Mare Turf as planned. But O’Brien already dialed in a contingency plan, one illustrating his endless barn depth.

“Santa Barbara picked up a little setback, so Mother Earth will take in some of the races that Santa Barbara was being aimed at,” O’Brien told the Racing Post.

In essence, O’Brien is replacing one Group/Grade 1 winner with another. Mother Earth won the 1,000 Guineas at Newmarket in the spring and the Group 1 Prix Rothschild at Deauville on Aug. 3. She’s 2-for-6 this year, hitting the board all six times (2-2-2). According to the Racing Post, Mother Earth was headed to Australia for the Golden Eagle, one of that country’s richest races.

Mother Earth is O’Brien’s little helper

Instead, O’Brien told the publication he may send Mother Earth to either the Sun Chariot Stakes at Newmarket or to Keeneland for an unspecified Breeders’ Cup prep race. That race would need to be soon, since the Breeders’ Cup is Nov. 6 at Del Mar.

Santa Barbara was the 11/4 overseas favorite on Oddschecker to win the Breeders’ Cup Filly & Mare Turf. That race was shaping up to be one of the event’s best, with Santa Monica, War Like Goddess (5/1), and Snowfall (11/2) set to tangle.

As for St Mark’s Basilica, O’Brien said the colt suffered an infected hind leg even before he won the Irish Champion Stakes at Leopardstown on Sept. 11. The five-time Group 1 winner suffered the injury when his front shoe detached and hit his hind leg. That leg became infected.

Injury and all, St. Mark’s Basilica still won a Group 1

Even then, St Mark’s Basilica beat reigning Breeders’ Cup Turf champion Tarnawa and Poetic Flare in the Irish Champion Stakes. Before that, O’Brien scratched him from the Juddmonte International and told reporters St Mark’s Basilica – who is undefeated in four 2021 races – hasn’t shaken the wound as easily as he’s shaken opponents.

“Usually, they would be back by now, but he’s not,” O’Brien told the Racing Post. “When we went back into full canters with him, he was a little bit sore, so we had to pull back and go slow. So that’s where we are with him for the moment.”

For the moment, St Mark’s Basilica is one of the best horses in Europe. He’s won his last five races – all Group 1s – dating to the Dewhurst Stakes at Newmarket last October. The five victories came on five different tracks: Newmarket, Longchamp (Poule d’Essai des Poulains), Chantilly (Prix du Jockey Club), Sandown Park (Eclipse Stakes), and Leopardstown (Irish Champions).

This, on top of his nearly $3 million in earnings.

Oddschecker put him as the 6/1 second-favorite to win the Breeders’ Cup Turf, behind 4/1 co-favorites Mishriff and Tarnawa.