The transaction wire was humming on Tuesday.

That was the deadline for all 30 teams to make decisions about which players to put on the 40-man roster. Many prospects were added to protect them from the Rule 5 Draft.

Players first signed at age 18 or younger must be added to 40-man rosters within five seasons or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 years or older have to be protected within four seasons. Clubs pay $100,000 to select a player in the Major League phase of the Rule 5 Draft. If that player doesn't stay on the big league active roster for the full season, he gets offered back to his former team for $50,000.

For this year, that means an international or high school Draft pick signed in 2019 had to be protected. A college player taken in the 2020 Draft was in the same position. There were six players on MLB Pipeline’s Top 100 Prospects list who needed to be protected, led by No. 21 overall Adael Amador of the Rockies. All of them were added to their club's rosters. A total of 54 prospects on Top 30 lists also earned 40-man spots.

There were additional names added to rosters on Tuesday, prospects who, although they are not ranked, are worth monitoring. Of the 10 unranked prospects mentioned a year ago, seven spent time in the big leagues in 2023. The list from the prior year featured the Guardians’ Steven Kwan, who finished third in 2022 Rookie of the Year voting, and Orioles reliever Félix Bautista, who was an All-Star closer in 2023 before needing Tommy John surgery.

Below are seven unranked prospects who earned a 40-man spot before the deadline. Many of them could be at a big league ballpark near you in 2024.

Bailey Horn, LHP, Cubs: Originally taken by the White Sox in the fifth and final round of the 2020 Draft out of Auburn, Horn was shipped to the Cubs at the 2021 Trade Deadline for Ryan Tepera. He’s spent the past two seasons pitching out the bullpen, and while his command needs work (4.9 BB/9 in 2023, in line with his career rate), he’s missed a ton of bats (11.3/9 this past season) with a fastball that now touches 97 mph, a low-80s slider and a slower curve.

Jacob Hurtubise, OF, Reds: After four years at Army, Hurtubise joined the Reds as a nondrafted free agent following the shortened 2020 Draft. His 70-grade speed is his carrying tool, and he stole 45 bags (and then went 11-for-11 in the Arizona Fall League) during a breakout 2023 season in which he hit .330/.479/.483 and led the organization with 163 wRC+. He can play all three outfield spots and walks nearly as frequently as he strikes out.

Christian Roa, RHP, Reds: A product of Texas A&M, Roa was a second-rounder in 2020. He’s always missed bats, 11.3 K/9 in his Minor League career and 12.7/9 in 2023 while reaching Triple-A. His fastball averaged around 94 mph this past year, touching 98, his mid-80s slider produced a 41 percent miss rate, and he can mix in a curve and changeup as well. The one thing holding him back is his command, with a 5.7 BB/9 rate (6.8 in 2023), making one wonder whether he's best suited for a bullpen role.

Cade Smith, RHP, Guardians: An undrafted free agent who signed with Cleveland after the 2020 Draft, Smith racked up 15 saves between Double-A and Triple-A in 2023, holding hitters to a .228 batting average and striking out 13.6 per nine. He ran his fastball up to 98 mph, averaging 94.5 mph, and his low-80s slider is his go-to secondary offering.

Angel Chivilli, RHP, Rockies: Chivilli, who signed for $200,000 in July 2018, spent some time on the Rockies’ Top 30 early in the 2023 season. He didn’t make his full-season debut until 2022 and collected 10 saves with Single-A Fresno that year. He saved 17 more with High-A Spokane and earned a promotion to Double-A this past season. His mid-90s fastball has good life, and he has a good, hard late-breaking slider and can mix in a solid changeup as well, though he was a bit too hittable in 2023 (9.7 H/9, .273 BAA).

Juan Mejia, RHP, Rockies: Mejia’s surface numbers in 2023 weren’t earth-shattering (5.06 ERA, for example), but he did reach Double-A and struck out 13.9 per nine. What might have made it necessary to add him to the roster was his Fall League performance, where he struck out 17.3 per nine with a 2.16 ERA and three saves in eight appearances. He needs to improve his command (4.9 BB/9 in 2023; 9 BB in 8 1/3 IP this fall), but his fastball-slider combination has a chance to make the grade.

Kai-Wei Teng, RHP, Giants: Teng began his career with the Twins, but the Taiwanese right-hander was sent to the Giants in 2019 in the Sam Dyson deal. He split the year between Double-A Richmond and Triple-A Sacramento, striking out 11.7 per nine over 126 1/3 IP. His low-90s sinking fastball tops out at 96 mph with a little cutting action, and he leans on a mid-80s slider that generated a 46 percent miss rate this past season. He can also mix in a curve and a changeup, and if the 6-foot-4 right-hander can find the strike zone more consistently, he could be a workhorse-like starter.