Trainer Mike Mitchell will undergo surgery Friday to remove a brain tumor that was diagnosed early this week, according to Daily Racing Form reports.
Mitchell, 64, was admitted to USC Medical Center on Wednesday, his wife, Denise, told the Form.
The Southern California-based horseman does not know if the tumor is malignant or benign; tests are expected to make a determination early next week. An MRI taken Monday revealed the tumor, which Denise Mitchell said was "medium-sized."
Mitchell's most recent stakes victory came with Potesta in the Hollywood Oaks on Saturday. His runners have taken 2,595 victories while earning a total of $62,880,930 in purses. His Grade 1 winners include Ever a Friend, Star Over the Bay, Kela, Romance is Diane, and Monzante; he is also responsible for the graded stakes wins of St. Trinians, On the Acorn, Kessem Power, and Skip to the Stone.
Mitchell has won six Del Mar training titles and 17 overall on the Southern California circuit. As well as being the winningest trainer at Del Mar, he is third behind legends Bobby Frankel and Charlie Whittingham at Betfair Hollywood Park.