We are inching closer and closer to Opening Day for the 2020 MLB season. That means that the Minor League season is also just around the corner. With that comes exciting new breakout prospects, as they rise up from both likely, and unlikely, places.

In the past few years, I’ve recommended a number of key pop-up prospects. Back at the end of 2017, I suggested that a little-known Yankees prospect named Jonathan Loaisiga deserved attention. In the spring of '19, I pointed to Yoendrys Gomez as a player to monitor. He’s now ranked among the Yankees' top 8-12 prospects in a number of different prospect publications. In the middle of '18, I ranked Julio Rodriguez as the Mariners’ fifth-best prospect, and then followed that up with a detailed explanation in April '19 that, “It was time to get excited about Julio Rodriguez.” In July '17, when he was still a Cardinals’ prospect, I first pointed to Zac Gallen as a future big-league contributor.

So, who can we uncover this spring? Today, we’re going to look at 10 deep sleeper prospects in Dynasty Leagues that shouldn’t be rostered just yet, but have a chance to find themselves on your rosters at year’s end.

Get any full-season MLB Premium Pass. Get access to our exclusive articles, rankings, projections, prospects coverage, 15 in-season lineup tools, daily expert DFS research, powerful Research Station, Lineup Optimizer and much more! Sign Up Now!

Brandon Howlett (3B, BOS)

Howlett is a raw prospect. He spent the 2019 season in Class A ball at the age of 19 and needed a solid .337 BABIP to help him hit .231. The strikeout raw was also sky-high at 31% -- so why am I keeping an eye on him? In his first two seasons, Howlett has produced line-drive rates of more than 25%.

It’s rare to see that kind of consistent hard-hitting among such a young, inexperienced player. And along with the developing pop comes a strong willingness to take a free pass. His walk rate is close to 13% at this point in his career. He was hitting pretty well during his first taste of full-season ball in '19 before appearing to tire in July and August.

Brayan Rocchio (SS, CLE)

I thought 2019 would be Rocchio’s big breakout season, but he merely held his own in the New York-Penn League at the age of 18 while predominantly playing against 21- and 22-year-old former college players. He struggled early but managed to produce at a slightly-above-average rate with a 107 wRC+. Rocchio really turned things on in August and hit .283/.349/.414 with six steals in seven attempts over 25 games.

He may never be a huge home run hitter, but the switch-hitting shortstop has the skill to slug 15 home runs, steal 20 or more bases and hit .300. He should get his first taste of full-season ball in 2020 and has looked good so far in Cleveland’s big league camp while filling in for the Major League hitters (3-for-6 with a home run).

Bryant Packard (OF, DET)

I personally thought Packard would be a decent late second-round or third-round Draft pick in 2019 out of East Carolina University. But he slipped to the Tigers in the fifth round, likely over concerns about his modest defensive skills. He hit .358 with a .994 OPS in his junior year of college after producing outstanding numbers in his sophomore season, too.

In his pro debut, Packard stung the ball during his first two stops in the lower levels of the Minors with a line-drive rate of more than 30%. At 6-foot-3 and 200 pounds, he has excellent size and just needs to make swing adjustments to get balls into the air more consistently. If he does that, the left-handed power hitter could really take off.

Olivares has been the victim of the Padres’ strong organizational outfield depth. Last year in Double-A, he produced a 123 wRC+ as a 23-year-old. He also has excellent speed and nabbed 35 stolen bases in 45 tries, one year after going 21-for-29 at Class A Advanced.

Olivares also has the potential to develop into a 20-20 hitter after hitting double-digit home runs over the past three seasons and gradually hitting more balls in the air. He hit a career-high 18 home runs in 2019, along with a 25.5% line-drive rate.

Davis Wendzel (3B, TEX)

I really enjoyed what the Rangers did early in the 2019 Draft, as they nabbed two of my three favorite college third basemen in Josh Jung and Wendzel. The latter prospect hit well in all three seasons at Baylor University but really broke out in his junior year with a 1.094 OPS. He hit just eight home runs, but also saw 19 of his 65 hits go for doubles.

There’s power in the bat and some swing adjustments could help him tap into it. Wendzel showed an excellent eye at the plate during his college career and, although he appeared in just seven games after signing, he produced a BB-K rate of 5-6. He’s not the flashiest player, but this third baseman could develop into a well-rounded contributor in multiple categories.

Lopez has been criminally overlooked during the past year or two. He spent the 2019 season in Class A where he hit .324 as a 20-year-old. His production has surpassed 130 wRC+ during the past two seasons, despite being young for the leagues at each stop. He likely gets passed over for more attention because he’s not a power hitter. His game is geared toward putting bat-to-ball and using his speed. He struck out less than 13% of the time in 2019, but also walked just 6.9% of the time.

Lopez has good speed but is still learning to run the bases effectively; he was nabbed 15 times in 35 attempts. Although he’s not the biggest player, he has strong wrists and forearms and could eventually be good for 30+ doubles and 10-12 home runs. Along with his natural hitting ability and speed, Lopez has played multiple positions and thar versatility is quite valuable in fantasy baseball. He’s spent time at second and third base, shortstop, and all three outfield spots.

T.J. Sikkema (SP, NYY)

Sikkema was one of my favorite college pitchers available in the 2019 Draft as a potential late first-round or second-round pick -- the Yankees nabbed him 38th overall. He had an excellent pro debut, although he was kept to just four games. In that small sample size, Sikkema produced a K-BB of 13-1 with six hits allowed in 10.2 innings, after striking out 101 college batters in 88.2 innings.

He could easily jump to Class A Advanced in 2020 with his advanced pitchability from the left side. He’s undersized, but is difficult to hit because of his unconventional delivery and potential for three average-or-better offerings. Sikkema’s lack of size could make him prone to home runs if he struggles to get a solid downward plane on his offerings. He may end up as more of a No. 4 starter, but he has the potential to eventually offer strikeouts and wins.

Isaiah Campbell (SP, SEA)

Another pitcher I liked a lot from the early rounds of the 2019 Draft, Campbell was selected 76th overall by the Mariners. That selection could be a steal. He’s far more physical than Sikkema (above) at 6-foot-4 and 225 pounds. I give a slight edge to the Yankees’ development system over the Mariners', but Campbell has the ingredients to be a No. 3 starter.

He throws in the mid-90s with three secondary offerings and good control (22 walks in 118.1 college innings in '19). His height helps him get good downward plane on the ball, which in turn helps generate ground ball outs. If he shows a reliable strikeout pitch, then Campbell could be a quick mover through the system.

Jimenez is the rare Rule 5 Draft pick that has legitimate redraft and dynasty value. He was 25 years old at Double-A in 2019 and might look like a late-developer, but he wasn’t signed out of the Dominican Republic until he was almost 21 years old.

He then spent three years in Rookie Season ball. Last season split between Class A Advanced and Double-A, the hard-throwing right-hander struck out 93 batters with 21 walks in 59 innings. If he can find the plate consistently, Jimenez’s mid-90s fastball and promising curveball give him high-leverage potential.

Chris Vallimont (SP, MIN)

I was a fan of Vallimont when he was in the Marlins' system and I became even more endeared with him after he moved to the Twins’ superior development system. Between two organizations and three teams in 2019, the 6-foot-5 right-hander struck out 150 batters in 127.2 innings. Despite a fly ball heavy approach, Vallimont allowed just seven home runs.

Moving forward, he needs to find a third reliable pitch to go with his fastball and slider, while also showing improved control -- something that the Twins’ development staff has been successful with in the past. The club absolutely pulled one over on the Marlins in getting him during the Lewin Diaz/Sergio Romo trade last summer.