Adolph Krajewski, a longtime assistant to trainers Frankie Brothers and Al Stall Jr., died Monday morning at Our Lady of Lourdes Hospital in Lafayette, La., following a battle with leukemia. He was 65. Krajewski worked alongside Stall during the highly successful years that Brothers enjoyed in the 1980s before he became Stall’s top assistant when Stall went out on his own in 1991. “Adolph was a tireless worker and was fiercely loyal,” Stall said Monday from Saratoga. Krajewski, a native of Chicago, is survived by his son, Adolph Jr., who became well known as an exercise rider for the Phipps Stable before becoming a vanning agent, and by his two grandchildren. Funeral arrangements were unclear Monday, but Stall said a service probably would be held in New York at a later date.