MLB Pipeline will unveil its 2019 Top 100 Prospects list with a one-hour show on MLB Network and MLB.com on Saturday at 8 p.m. ET. Leading up to the release, we look at baseball's top 10 prospects at each position.
There is obviously a lot of turnover in the prospect world. Players graduate, they fall off lists, rankings change frequently. Yet the very top of this year's Top 10 third base propsects list is identical to last year's version.
Top 10 Prospects by Position
That's for good reason. Blue Jays phenom Vladimir Guerrero Jr. cemented his place atop this, and pretty much every, list with his 2018 season. And while the Reds' Nick Senzel missed time because of injury, he showed that his all-around toolset is just about big league ready.
There should be change at the top soon enough, with both Guerrero and Senzel likely to graduate off the list at some point in 2019. Whether they'll prove to be as successful as the best players from previous versions of this list remains to be seen. The Rockies' Nolan Arenado, No. 1 on the list in 2012, has the highest cumulative Wins Above Replacement (33.1 bWAR) of any player on this list since we began ranking the Top 10 prospects by position in 2011. The Cubs' Kristopher Bryant, who topped this Top 10 in 2015, is next at 21.6, while Nationals third baseman Anthony Rendon is third (21.1).
And there's continuity beyond the top of the list as well. With Michael Chavis still on the list, that makes six straight years the Red Sox have had at least one representative on this Top 10 (Garin Cecchini, 2014-15; Rafael Devers, 2014-17; Chavis, 2018-19). The Braves aren't far behind. Austin Riley is on the list for a fourth straight year, giving Atlanta five consecutive years of representation (Rio Ruiz, 2015).
The Top 10 (ETA)

1. Vladimir Guerrero Jr., Blue Jays (2019)
   
2. Nick Senzel, Reds (2019)
   
3. Austin Riley, Braves (2019)
   
4. Ke'Bryan Hayes, Pirates (2019)
   
5. Jonathan India, Reds (2021)
   
6. Alec Bohm, Phillies (2021)
   
7. Nolan Gorman, Cardinals (2022)
   
8. Nolan Jones, Indians (2020)
   
9. Ryan Mountcastle, Orioles (2019)
   
10. Michael Chavis, Red Sox (2019)
    Complete list »
    Top tools
    Best Hitter: Guerrero (80)
    It's the first 80 hit grade we've ever given out, and for good reason. Guerrero now has a career .331/.414/.529 line heading into 2019, and he flirted with .400 for much of '18, finishing at .381/.437/.636 in Triple-A, at age 19. He's walked (146) more times than he's struck out (135) in his career.

Best Power: Guerrero (70)
He had 13 homers and 43 extra-base hits while slugging .485 as an 18-year-old in 2017. Last year, he upped that to 20 home runs, 50 extra-base hits and a .636 slugging percentage. The arrow is still pointing up for him in terms of his power potential, with 30-plus homers extremely realistic in the big leagues.
Fastest Runner: Senzel (60)
Senzel's speed has helped him to reach double-digits in steals in both 2016 and '17, and he's swiped 40 bases in 231 Minor League games through 2018. His athleticism has also allowed him to move around the field in addition to showing excellent range at the hot corner, showing an ability to play second and even a little shortstop, while trying the outfield on for size as well.

Best Arm: Guerrero, Senzel, Riley, Hayes, Jones (60)
All five have plus arms and may have flashed better than 60-grade at times. Riley was a pitcher in high school, one who was up to 92 mph from the mound as a senior, so we'll give him the slight edge.

Best Defender: Hayes, Senzel (60)
Hayes was the third baseman on this year's All-Defense Prospect team, thanks to his outstanding range, hands, instincts and arm. Senzel isn't far behind and might only be 1A to Hayes because he missed time due to injury.

Superlatives
Highest Ceiling: Guerrero
Guerrero is one of the best offensive prospects we've ever seen, one who should hit well over .300 and hit more than 30 homers annually. That's a perennial All-Star, one who could wow big league crowds for a very long time to come.
Highest Floor: Guerrero
At worst, Guerrero moves to first and maybe doesn't hit more than 30 homers per year. He's as sure a bet to hit in the Majors as any prospect to come through a farm system.
Rookie of the Year Candidate: Guerrero
Senzel is competing for an Opening Day spot on the Reds' roster and if he stays healthy, he could compete for National League honors. But even if Vladdy starts the year in Triple-A, the impact he should have on the Blue Jays' roster should make him a front-runner in the American League.
Highest Riser: Riley
Everyone on this list came in with some prospect stock, but Riley has moved the most, especially considering many teams liked him as a pitcher coming out of high school in 2015. Then there were those who doubted he'd hit enough to tap into his considerable raw power. He debuted on the Braves' Top 30 at No. 20 post-Draft and initially moved up and down that list before cracking the Top 10 3B list in 2017.
Humblest Beginning: Jones
Everyone on this list was a first- or second-round pick, or a big international signing, so it's tough to give anyone this crown. Jones signed for nearly twice slot value in the second round. He had a rather humble pro debut in the rookie-level Arizona League and then spent a second summer in full-season ball. He really jumped up in 2018 by playing across two levels of Class A ball and reaching the Top 100 overall.

Most to Prove: Chavis
Chavis played in only 46 games in 2018 after serving an 80-game suspension for testing positive for a performance-enhancing substance. Then he was unable to play in the Arizona Fall League to make up for lost time because of injury. He's eager to prove to the Red Sox that he's still the potential run-producer he looked like he was becoming after a huge 2017 campaign.

Keep An Eye On: Colton Welker, Rockies
All the 2016 fourth-round pick has done is hit, even when missing time because of injury. He's never hit below .329 in any of his three stops and carries a .337/.383/.492 line into his 2019 season, when he'll be making the move up to Double-A.