DUNEDIN, Fla. -- Since the Blue Jays drafted David Wells and Jimmy Key in the second and third rounds in 1982, they haven't signed another left-handed pitcher who blossomed into an All-Star as a starter in Toronto. But that drought could soon come to an end.

On MLB Pipeline's recently released Blue Jays Top 30 Prospects list, the top spot and four of the first 10 were claimed by left-handers: Ricky Tiedemann (No. 1 and No. 29 on the overall Top 100), Brandon Barriera (No. 4), Adam Macko (No. 9) and Kendry Rojas (No. 10).

A third-round pick out of Golden West (Calif.) JC in 2021, Tiedemann has three plus pitches in a mid-90s fastball with carry, a sweeping low-80s slider and a sinking mid-80s changeup. He has limited opponents to a .168 average while striking out 199 in 122 2/3 innings as a pro, but he also worked just 44 frames last year while dealing with shoulder and biceps issues and never has gone into the sixth inning in 33 starts. He did finish strong in 2023, posting a 1.98 ERA in his final four starts in Double-A and Triple-A before winning Arizona Fall League pitcher of the year honors.

• MLB Pipeline | Top 100 prospects | Prospect video

"It's all about health with Ricky," Toronto farm director Joe Sclafani said. "He lost his feel for his changeup a little bit last year after it used to be the most comfortable pitch for him. The slider is really good and the heater is obviously really good. He's going to get back to using his changeup more.

"His routines are good and he's on top of stuff. He's still figuring sequencing and the strike zone but he's pretty close."

With three solid or better pitches and the potential for control to match, Barriera has a ceiling close to Tiedemann's. But the 23rd overall choice in the 2022 Draft out of a Florida high school had shoulder issues during his first Spring Training, came down with a sore elbow four starts into his pro debut last May and made just three more appearances before biceps soreness shelved him again. His conditioning wasn't as sharp as it could have been and his stuff rarely was at its best a year ago, but he's poised for a much better second season.

"Brandon has worked hard," Sclafani said. "He gained a little bit of weight last year but he has cleaned it up and lost 20 pounds. He looks more like the amateur version of himself. He's moving better and he has been 93-95 mph in early bullpens."

Macko was born in Slovakia and grew up in Ireland before playing high school ball in Canada and going in the seventh round of the 2019 Draft to the Mariners. He had trouble staying healthy before coming to Blue Jays in the Teoscar Hernández trade following the 2022 season, then compiled a career-high 20 starts and 86 innings last summer. He more regularly hit the mid-90s with his fastball and turned his downer curveball into a consistent plus pitch.

"When we got him, we told Adam that a successful year for you will be staying healthy for the whole year, so that was a good start," Sclafani said. "He didn't have feel for his sweeper, so we banged that in July and he gained three mph on his heater and his curve came on. There was no one better in the system in his last six or seven starts. It was cool to see his confidence grow as the season went on."

Signed out of Cuba for $215,000 in November 2020, Rojas has a low-90s fastball that plays up because he gets very good extension in his delivery and backs it up with a solid low-80s slider. He'll focus on maintaining his stuff deeper into games and the season after recording a 3.75 ERA with 82 strikeouts in 84 innings last year in Single-A.

Connor O'Halloran, a fifth-rounder out of Michigan last July, is an unranked southpaw to watch. The son of former big leaguer Greg O'Halloran and the 2023 Big Ten Conference pitcher of the year, he stands out more with his control and deception than his pure stuff, which is highlighted by his low-80s slider. Sclafani said the Blue Jays see some opportunity to add some velocity to his fastball, which sits around 89 mph, and lauded his ability to keep batters off balance.

• Subscribe to the MLB Pipeline Newsletter

Camp standout: C.J. Van Eyk

Van Eyk had Tommy John surgery a year after the Blue Jays drafted him in 2020's second round out of Florida State, lost all of 2022 while rehabbing and pitched just 34 1/3 innings last summer. The right-hander made up for some lost time in the Arizona Fall League, where both his sinker and his curveball ranked among the best in the development circuit, and looks ready to take off in what should be his first fully healthy pro season.

"C.J. has been the most exciting guy in camp," Sclafani said. "He picked up a two-seamer, a bowling-ball sinker, right before he got to the AFL and we were very encouraged by how he did there. He can ride a four-seamer up, a two-seamer down, the curve is still pretty good and he's tinkering with his changeup. He looks like the guy we drafted."

Spring Breakout sleeper: Landen Maroudis

Part of one of the deepest prep pitching staffs in the nation last spring at Calvary Christian HS in Clearwater, Fla. -- five miles from the Blue Jays' training base in Dunedin -- Maroudis signed for an over-slot $1.5 million as a fourth-rounder. The right-hander has yet to make his pro debut, so fans could get their first glimpse of his mid-rotation upside in Toronto's Spring Breakout game against the Yankees on Saturday.

"We were obviously excited about his athleticism coming in," Sclafani said. "He has been here all offseason and worked hard. Now he's a monster. He was 91-93 in high school and now he's sitting at 94 this spring with good feel for his breaking ball. It's not quite the jump that Ricky [Tiedemann] made in his first Spring Training, but it's close."

Breakout potential: Enmanuel Bonilla

Toronto gave the bulk of its 2023 international bonus pool money to Bonilla, signing the Dominican outfielder for $4.1 million. He offered some of the best bat speed and power potential in last year's market, and he's much more physical than his listed 6-foot-1 and 180 pounds. After batting .307/.407/.429 with three homers in 50 games in the Rookie-level Dominican Summer League, he'll make his U.S. debut in the Rookie-level Florida Complex League in May.

"Physically, you look at him, and it doesn't make any sense that he's going to play this year as an 18-year-old," Sclafani said. "He a tremendous kid who asks a lot of questions and works hard. He checks all the boxes with his intangibles.

"He needs to work on his defense. He didn't light it up in terms of things like home runs and slugging, but he showed an advanced approach. He's so physically gifted."