The 25-year-old Hudson believes he has a full tear of the ulnar collateral ligament, but won't declare his season is over until he gets a second opinion from Dr. Lewis Yocum in Los Angeles on Friday.
''It was a shock,'' he said in a conference call with reporters on Thursday. ''It's something nobody wants to hear. Probably the worst news you can get.''
Hudson said that he has ''a significant tear in there, it looks like.''
Hudson left Tuesday's game against Atlanta, saying afterward that his elbow didn't feel 100 percent earlier this season.
But the pain he felt this week is much worse than he felt earlier this year.
Hudson denied he was pitching with a major injury.
''If I would have felt I couldn't execute a pitch,'' he said, ''I would have taken myself out.''
After going 16-12 with a 3.49 ERA in 2011, Hudson has struggled in his second season with Arizona and spent April 21-May 27 on the disabled list with a right shoulder impingement.
Hudson gave up five runs and seven hits in 1 2-3 innings on Tuesday, raising his ERA to 7.35.
The Diamondbacks called up 21-year-old Trevor Bauer, the No. 3 overall draft pick of 2011, to make his major league debut .
Arizona's starting rotation was hurt last Saturday when Joe Saunders went on the disabled list with a strained left shoulder.