If the Blue Jays don't keep him on their 25-man roster, he'll again be exposed to waivers.
Montero, 26, was regarded as one of baseball's top right-handed-hitting prospects when he was coming up with the Yankees, but he's never consistently produced at the Major League level since being acquired by Seattle in a deal for right-hander Michael Pineda in 2012.
Montero's best season was as a rookie that year, when he batted .260 with 15 homers and 62 RBIs while splitting time between catcher and designated hitter. But he batted .208 in 29 games to start the 2013 season, was sent to Triple-A. He then drew a 50-game suspension from Major League Baseball.
He spent most of the past two seasons in Triple-A and hit well for Tacoma, but he posted just a .223 average and five homers with 19 RBIs in 38 games last year in several short stints with the Mariners.
Montero transitioned to first base and lost about 35 pounds over the past two seasons. He came to camp this spring looking to compete for backup roles at first base and DH, but hit just .237 with 12 strikeouts in 38 Cactus League at-bats.
• The Mariners rolled out a lineup that appeared very close to an Opening Day group on Monday, with the exception of Daniel Robertson starting in right field instead of Seth Smith or Franklin Gutierrez. Kyle Seager was batting No. 2 behind Norichika Aoki, but manager Scott Servais said it's not yet determined whether Seager or Ketel Marte will fill that spot in the regular season.
"That final decision hasn't been made yet," he said. "I like our lineup. I've liked it all spring. I think we're swinging the bat very well right now. We've been scoring runs in a variety of ways. Some days it's the home run, other days it's stealing bases. We're just trying to group similar type hitters and players. I'm not sure if Kyle ends up 2 or 5 or 6. Whatever. As I've said all along, Kyle will give us a good at-bat. I have no concerns there."
• The Mariners' rotation is set for the rest of spring. Taijuan Walker will face the Indians on Tuesday night, followed by Felix Hernandez on Wednesday vs. the Padres, Hisashi Iwakuma in a Minor League game Thursday, Wade Miley on Friday night vs. the Rockies and Nathan Karns in Saturday's Cactus League finale against the Rockies in Scottsdale.
• Servais said he'll stick with his full five-man rotation in the opening week despite an off-day after the opening series at Texas. That means Hernandez, Iwakuma and Miley will face the Rangers, with Walker getting the home opener on April 8 vs. the A's.
Karns will pitch April 9 against the A's, and Hernandez is lined up for his first King's Court appearance at Safeco Field on Sunday, April 10, in that series finale.
• Right-hander Joel Peralta has made the team as a 40-year-old non-roster invitee, with Servais saying he'll likely be used in sixth- and seventh-inning situations. The skipper likes his veteran presence, but notes it takes more than that to help a team.
"He's been a nice addition in our clubhouse," Servais said. "But you can be the greatest guy in the world, you've got to get 'em out. I think for what he brings and how he goes about his business, he's been in a lot of situations and has a ton of experience. I feel very comfortable throwing him in there. I don't see him pitching in the back of the game, but more sixth- seventh-inning type of work and see where it goes from there. I'm glad to have him on the club."