Silseth underwent season-ending surgery on his right elbow Tuesday, Jeff Fletcher of The Orange County Register reports.
The specifics of Silseth's operation are unknown, but he didn't receive Tommy John surgery and is expected to be fully recovered by the time spring training begins. The 24-year-old righty allowed six earned runs in eight innings over two big-league starts this year, and he'll finish with a 6.35 ERA through 28.1 frames in Triple-A.