Ruperto Donoso was required to do mandatory service with the Chilean Army and as such did not race in 1942 and 1943, returning on July 24, 1944 to compete at New York's Belmont Park.
Triple Crown series, superstar jockey Eddie Arcaro rode Phalanx to a second-place finish in the Kentucky Derby and to a third in the Preakness Stakes.
It was then that trainer Syl Veitch decided to replace Arcaro with the C. V. Whitney stable's secondary jockey in the Belmont Stakes.
Donoso had ridden Phalanx to two wins in 1946 but as the stable's first string jockey, Arcaro had had first choice on all mounts.
[1] Among his other success, Donoso guided Many Stings to a half-length victory over Big Pebble and fourteen other runners in the Widener Challenge Cup at Hialeah Park.