Triple-A Colorado Springs reliever Ryan Mattheus has a torn ulnar collateral ligament in his right elbow and will undergo a ligament transplant or Tommy John surgery in the next week or two when the swelling subsides. Matteus, 25, will be sidelined for at least a year after the operation.

This has been a starcrossed season for Mattheus, who went 1-1 with a 4.32 ERA in 13 games for the Sky Sox. He also pitched at high Class A Modesto and Double-A Tulsa, working a combined total of just 26 innings this season as he dealt with a strained oblique and an eye injury he suffered in a weight-room accident.

In other farm news, Connor Graham is scheduled to start Friday for Modesto and throw about 60 pitches. He has been sidelined with right elbow inflammation and last pitched June 25 and is 4-4 with a 3.74 ERA.

Left-hander Christian Friedrich, sidelined since June 10 with left elbow inflammation, has been throwing bullpen sessions and simulated games and is likely to return to Modesto’s rotation next week, possibly Tuesday.

Modesto starter Bruce Billings is still in the rest-and-treatment mode for his shoulder tendinitis and has yet to start a throwing program. He last pitched June 19 and is 5-7 with a 4.59 ERA.