ARLINGTON, Texas -- Mariners starter Marco Gonzales remained in Seattle for tests on his left forearm and will not make his scheduled start against the Texas Rangers on Saturday, manager Scott Servais said.

Servais said Gonzalez felt discomfort after throwing 5 2/3 innings last Sunday at home against Pittsburgh. The left-hander still wasn't feeling right when throwing his bullpen session earlier this week.

"Wanted to get it checked out," Servais said Friday, adding that he wouldn't elaborate further until the team gets reports back from the doctors.

Mariners right-hander Bryan Woo will pitch in Gonzales' spot in what will be his big league debut. The team will have to make a roster move before Saturday's game to add him to the roster.

Seattle has won six of the last seven games started by Gonzales (4-1, 5.22 ERA).

Gonzales allowed one run on three hits over 5 2/3 innings against Pittsburgh, after giving up two runs over six innings against Oakland his previous start. Those followed his shortest outing of the season, when Boston scored eight runs over 1 2/3 innings against him.

Woo is 3-2 with a 2.33 ERA with 32 strikeouts and eight walks over 27 innings in five starts for Double-A Arkansas. The 23-year-old right-hander was a sixth-round draft pick by the Mariners out of Cal Poly in 2021.