EUGENE — Oregon has now lost two-thirds of its projected starting rotation to Tommy John surgery.

EUGENE — Oregon has now lost two-thirds of its projected starting rotation to Tommy John surgery.

The Ducks, who moved up four spots to No. 19 in this week's Baseball America Top 25, announced Monday that freshman left-hander Matt Krook will undergo surgery on his left elbow today and miss the rest of the season. The procedure will be performed by the famed Dr. James Andrews.

Krook was 2-1 with a 1.79 ERA in eight starts. He was the Ducks' No. 2 starter and had 60 strikeouts.

Krook was injured in the third inning of his start against Washington on April 5. He had an MRI the following week and then got a second opinion Monday.

Oregon coach George Horton was prepared for the worst-case scenario last week.

"My heart goes out hoping for the best for Matty and his family," Horton said. "When my head hits the pillow, I will say a couple prayers for him and his family."

Horton expected to have a rotation that featured Cole Irvin, Tommy Thorpe and Krook, but Thorpe is the only one of still active. Irvin, who led the Ducks with 12 wins last year, was lost before the season after undergoing Tommy John surgery.

Horton said either freshman Trent Paddon or senior Brando Tessar will start on Sunday when the Ducks close out a three-game series at No. 5 Oregon State.

"We will evaluate that, look at tape, and decide if it is Tessar or Paddon," Horton said.

Paddon has replaced Krook during the past two weekends and is 1-2 with a 3.03 ERA in 13 games this season. He earned his first win Sunday when he allowed five hits and one run in six innings in a 2-1 victory over Washington State.

"He was better than his last start, which I expected," Horton said. "His secondary pitches were a little better and I thought he was a little more in character emotionally. I thought it was a nice reward for a good effort that he was the winning pitcher."

Paddon said he will be ready if he stays in the rotation.

"If I am, I'll be right back up there throwing strikes," he said. "That will be exciting."

Tessar has thrown seven scoreless innings in back-to-back weekday starts and is 3-0 with a 2.73 ERA. He was Oregon's Sunday starter as a sophomore and said he would welcome a return to that role.