A hand surgeon has confirmed a diagnosis of tendinitis in the middle finger of Randy Johnson’s left hand, Seattle Mariners team physician Dr. Larry Pedegana said.

Dr. John Sack examined Johnson’s pitching hand Tuesday.

Johnson is being treated for the tendinitis, and his progress is being monitored, Pedegana said.

Johnson, who hasn’t pitched since Aug. 20 against Cleveland, will miss his third consecutive start tonight and is doubtful for Monday, the Mariners said.

Johnson, 33, has a 17-4 record with a 2.32 ERA in 26 starts this season. The Mariners are 19-7 in games started by the 6-foot-10 Johnson this season.