The Orioles called up infield prospect Connor Norby for their series in Toronto, and the 23-year-old will make his major league debut Monday night starting at second base and batting ninth. He will wear No. 12.

Norby, whom Baltimore drafted in the second round of the 2021 draft out of East Carolina, ranks as the Orioles’ No. 6 prospect, according to MLB Pipeline. He has long impressed with his bat since he was drafted. This season, in 51 games for Triple-A Norfolk, Norby is hitting .286 with an .884 on-base-plus-slugging percentage.

The promotion comes as the Orioles played infielder Jorge Mateo, who was inadvertently hit on the back of the helmet by Cedric Mullins while in the on-deck circle, on the seven-day concussion injured list. Manager Brandon Hyde said Sunday that Mateo was in concussion protocol.

Norby would need to be added to the 40-man roster; there’s currently an opening, with 39 players active. Norby primarily plays second base, although he can slot into a corner outfield position.

The Orioles have the best farm system in baseball, and Norby is one of several infielders who rank highly. Jackson Holliday, the unanimous No. 1 prospect, will surely be in the majors again at some point after he struggled in his first 10-game sample. Coby Mayo, who’s primarily a third baseman, is close to reaching the majors as well, although a broken rib is holding him in Triple-A for now.

The Orioles are also recalled left-hander Nick Vespi to Toronto, a relief pitcher who has been up and down between Triple-A and the majors several times this season. Vespi pitched a scoreless inning for the Orioles last month and holds a 2.96 ERA for the Tides thus far.

In a corresponding move, the team designated right-handed reliever Thyago Vieira for assignment. A recent acquisition from the Milwaukee Brewers, Vieira made one appearance with the Orioles and gave up three earned runs without recording an out.