Comer, the Republican state agriculture commissioner, is seeking the party's nomination for governor in 2015. Former Louisville Metro Councilman Hal Heiner is also seeking the Republican nomination.
In a news release from the Comer campaign, Whitfield said he believes Comer's achievements as agriculture commissioner makes him the candidate with the best chance to take back the governor's office. Democrats have won nine of the last 10 governor's elections.
Whitfield has represented Kentucky's 1st Congressional District since 1994. The district includes the city of Tompkinsville, Comer's home. Former Republican U.S. Rep. Anne Northup and several state lawmakers also have endorsed Comer.
Attorney General Jack Conway is the only announced Democrat in the race. He has endorsements from former U.S. Sen. Wendell Ford, former state Auditor Crit Luallen and Democratic U.S. Rep. John Yarmuth.