Aidan O’Brien saddles three of the 12 expected runners in the last Group 1 of the English flat season, the Racing Post Trophy on Saturday at Doncaster. If one of the O’Brien three wins, he will break Bobby Frankel’s record of 25 Group 1 or Grade 1 winners in a calendar year. If he strikes out Saturday, he has runners in a pair of French Group 1’s for 2-year-olds next weekend, and as many as 14 horses for Grade 1 races during the two-day Breeders’ Cup meeting at Del Mar. Saxon Warrior, the mount of Ryan Moore, is the early betting choice in the one-mile straight-course Racing Post Trophy. Saxon Warrior, by the Japanese stud Deep Impact and out of the Galileo mare Maybe, has started his career with two wins. Going one mile in Ireland in both starts, he won a maiden race at Leopardstown and the Group 2 Beresford at Naas, a race in which Delano Roosevelt, a stablemate that had a big early-season reputation, finished second. Saxon Warrior won the Beresford by more than two lengths while showing tactical pace that should stand him in good stead Saturday. The Pentagon, another O’Brien entrant, debuted with a modest sixth over soft ground at The Curragh but went much better on good ground winning a maiden race and, most recently, the Group 3 Tyros Stakes at Leopardstown in July. The longest price among the O’Brien three is Seahenge, but don’t sell him short. He was a well-beaten third to Breeders’ Cup-bound stablemates U S Navy Flag and Mendelssohn last out in the Group 1 Dewhurst, but got off to a terrible start in that race and had further trouble a quarter-mile from the finish. Verbal Dexterity and Roaring Line have the best chance to deny O’Brien the Frankel record. Verbal Dexterity already is a Group 1 winner for trainer Jim Bolger, having captured the Group 1 National Stakes on Sept. 10 at The Curragh. Second by more than three lengths in that race was Beckford, who has a decent chance in the BC Juvenile Turf. Roaring Lion, from the John Gosden barn, initially was thought to be Breeders’ Cup bound, but stays home for the Racing Post Trophy instead. Roaring Lion has won all three of his starts and stepped up to group stakes competition for the first time winning the Group 2 Royal Lodge over Breeders’ Cup pre-entrant Nelson. Roaring Lion won that one-mile race by just a neck but appeared to idle once making the lead. Post time for the Racing Post Trophy, the fourth of seven races, is 10:25 a.m. Eastern.