SEATTLE -- The Seattle Mariners placed rookie right-hander Bryan Woo on the 15-day injured list Tuesday with inflammation in his right forearm.
Seattle is expected to fill Woo's spot in the starting rotation by promoting top pitching prospect Emerson Hancock from Double-A Arkansas. Hancock was in the clubhouse before Tuesday's game against San Diego, but Seattle was expected to wait on the roster move until Wednesday.
Woo pitched six innings Thursday against the Los Angeles Angels, allowing two runs and four hits. He didn't feel "100 percent" following a bullpen session, Mariners manager Scott Servais said.
"I thought he threw the ball outstanding the other night in Anaheim," Servais said. "And I don't think this is anything serious. It just didn't feel 100 percent, so we're giving him a chance to catch his breath."
Woo, 23, is 1-3 with a 4.75 ERA in 11 starts with Seattle since being promoted from Arkansas in early June. He has 60 strikeouts and 17 walks in 55 innings. The Mariners have acknowledged the need to monitor Woo's workload after he had Tommy John surgery in 2021.
Hancock, the No. 6 overall pick in the 2020 amateur draft, has spent each of the past two seasons in Arkansas. He has a 4.32 ERA in 98 innings this year, with 107 strikeouts and 38 walks.
The Mariners also designated right-handed reliever Matt Festa for assignment, recalled right-handed reliever Ryder Ryan from Triple-A Tacoma and claimed right-hander Ryan Jensen off waivers from the Chicago Cubs.