The Giants cut lefty Kyle Harrison from his starting position and placed him on the injured list

SAN FRANCISCO – The San Francisco Giants placed left-hander Kyle Harrison on the injured list with a sprained right ankle just hours before he was scheduled to start Sunday against the Los Angeles Angels.

Harrison rolled his ankle during a weight room workout Saturday and was unable to throw. Manager Bob Melvin had no timeline for his return.

“He’s definitely down,” Melvin said. “Sometimes these things just happen. Can happen anywhere. But working, preparing for your start, for it to happen like this is very disappointing.”

Reliever Erik Miller was scheduled to start for San Francisco in place of Harrison in the series finale as the Giants opted for a bullpen day in hopes of avoiding a three-game sweep. Miller made his fifth start of the season, but pitched fewer than two innings in his first four.

The move for Harrison was retroactive to June 13. Harrison is 4-3 with a 3.96 ERA in 14 starts for San Francisco this season. He allowed one run in 6 1-3 innings in a no-decision against Houston in his previous start on Monday.

Harrison’s injury is the latest to hamper the Giants’ rotation. San Francisco recently placed left-hander Blake Snell on the injured list due to a groin injury and has been without starters Robbie Ray, Alex Cobb and Tristan Beck all season.

“You can never have too much starting pitching,” Melvin said. “A number of boys are indeed coming back. That will probably take some time. Kyle has been very consistent for us, so in the meantime we’ll try to find another way around it. You’ll probably see a little bit more bullpen.

The Giants purchased the contract of right-hander Spence Bivens from Triple-A Sacramento to take Harrison’s spot on the roster. Bivens, 29, began his professional career in France and worked in the independent leagues before being signed by the Giants two years ago. Now he has reached the major league. He was 4-0 with a 2.81 ERA in 21 games for the River Cats this season.

“There are great stories and you always feel good when someone makes their major league debut,” Melvin said. “But when you know the trials and everything he went through, this is very special. … When he finally makes it to the big leagues, it really gives you goosebumps.”

Infielder Nick Avila was released to make room for Bivens on the 40-man roster.