Though Hernandez is slated to return next Wednesday and Walker could rejoin the club on its final road trip of the month, Servais said Montgomery is certainly under consideration to stick in a starting role.
"No doubt," Servais said. "He threw the ball great in Kansas City. He'll get another shot against a very good team here in Houston and we'll see how that goes."
With James Paxton, Hisashi Iwakuma and Montgomery facing the Astros this weekend, the rotation for the White Sox series next week will be Wade LeBlanc on Monday, Wade Miley on Tuesday and Hernandez on Wednesday.
Servais said that allows Miley to get a little extra rest after dealing with shoulder issues in recent weeks.
• Recent roster additions Daniel Robertson and Jesus Sucre were still with the team as the second half opened on Friday. Robertson has taken Norichika Aoki's spot in the outfield for now, while Sucre is filling in as the backup catcher until Mike Zunino is recalled.
Zunino figures to return in the next few days, but Aoki's situation sounds more tenuous.
"I know he's playing better down there," Servais said. "It's a matter of looking at our club and the fit there and when he does come back here. I think there's certainly a very good chance he will be back with us. The timing of that, I'm not quite sure right now. But we're watching it very closely every day."
• After dealing with a sore thumb on his right hand the last few games in Kansas City, first baseman Dae-Ho Lee was back to full strength and in the lineup on Friday.
• Safeco Field celebrated its 17th birthday on Friday. The ballpark opened on July 15, 1999, and is already the 15th-oldest stadium in the Majors.
• The Mariners had a minus-48 run differential at the All-Star break last year. This year they finished at plus-51. That 99-run improvement is fourth best in the Majors behind only the Cubs (123), Red Sox (109) and Indians (100).
• First-round Draft pick Kyle Lewis is on a roll at Class A Short-Season Everett, posting a .345/.433/.690 line with three doubles, four triples, three homers and 20 RBIs over his last 15 games going into Friday's play.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.