Montgomery, now vying for a southpaw specialist role, inherited a runner on second with one out in the fifth and immediately walked left-handed-hitting Adrian Gonzalez on five pitches. The lefty had a 2-0 count on Chase Utley before getting him to fly out and then struck out Austin Barnes to escape the jam.
"When you bring a reliever in, you want to attack and get that first guy out," manager Scott Servais said. "It wasn't quite there. But he got 'em out, and I think it's going to be a work in progress with Mike to understand what to do when he feels good coming out of the bullpen vs. when he doesn't feel good. Because he's still up and he's going to be coming in. He's aware of it."
With Charlie Furbush unlikely to be ready for the start of the season, Montgomery could find himself with one of the two lefty relief roles.
"The arm works and his stuff is really good," Servais said. "He's very comfortable against right-handed hitters as well because of the starting pitching innings he's got, so we'll keep working with him."
Zych, a rookie right-hander rated the 17th-best Mariners prospect, also appears headed toward a critical role, and he struck out two in a quick sixth.
"Tony was really good today," Servais said. "He mixed in two changeups, which we've talked about against left-handed hitters to get them off the fastball. I'm really glad to see him do it. Down here is where we need to do it."
Roach then finished things off by allowing three hits with no walks and three strikeouts in three innings, putting his spring ERA at 1.59 in 11 1/3 innings over five outings. The 26-year-old is likely headed for a starting role with Triple-A Tacoma, but he keeps pushing his way into the bullpen conversation.
"He can give you length," Servais said. "We want to keep him stretched out, so if it doesn't work in the bullpen, he's good to go and be an option for us in Tacoma. But yes, he is in the mix."
• Rob Brantly, claimed off waivers from the White Sox 10 days ago, is making things competitive with fellow left-handed hitter Steve Clevenger for the backup catching position behind Chris Iannetta. The Mariners knew he'd hit in the Minors, but they have liked what they've seen behind the plate as well.
"Defensively, he's probably been better [than expected]," Servais said. "He's made a little adjustment with his throwing, a minor tweak that [Minor League catching coordinator] Dan Wilson and I threw at him, and he's taken it and run with it. I like the player, I like what he brings. It makes it interesting for us. Another option."
• The Mariners have their first off-day of the spring on Tuesday, but left-hander James Paxton will stay on schedule by throwing about five innings in a Minor League game at 1 p.m. PT at the Peoria Complex.
• Outfielder Franklin Gutierrez was scratched from Monday's game against the Dodgers as the latest victim of the flu bug that's been going around Mariners camp.
• First baseman Dae-Ho Lee was not in camp Monday as he was excused to go visit his wife, who was about to give birth. Lee flew to Seattle on Sunday night and will also have the Tuesday off-day before rejoining the club on Wednesday.
• Outfielder Stefen Romero was back in the lineup after missing four days with cramping in his upper back. Romero went 0-for-3, lowering his Cactus League average to .429 (12-for-28).