PHOENIX, April 30 (UPI) -- Four-time reigning Cy Young Award winner Randy Johnson of the Arizona Diamondbacks will undergo arthroscopic knee surgery Thursday and is expected to miss three to six weeks.
The team made the announcement before Wednesday night's game with the Florida Marlins.
Johnson, 39, spent a stint on the 15-day disabled list due to a sprained right knee but was activated Sunday and pitched six solid innings in a 7-3 victory over the New York Mets, giving up two runs and nine hits while striking out 12.
But the pain persisted and the Diamondbacks decided to take care of the injury now rather than allow their star lefthander to pitch while injured.
The Diamondbacks also have been without righthander Curt Schilling, who went on the disabled list Monday after undergoing an appendectomy. He is expected to start Saturday.
After signing a two-year, $33 million contract extension prior to the season, Johnson has struggled. He is 1-2 with an 6.94 ERA in four starts.
Johnson is coming off another dominant season, one that resulted in his fourth straight Cy Young Award and fifth overall. With Arizona, Johnson is 81-29. He had not been on the disabled list since joining the Diamondbacks in 1999.
