| Name | State | School | Class | Pos. | Year | Round | Team |
| Andrew Abbott | VA | Halifax County | 2017 | LHP | 2021 | 2 | Reds |
| Mick Abel | OR | Jesuit | 2020 | RHP | 2020 | 1 | Philadelphia Phillies |
| Ben Abram | ON | Georgetown District | 2018 | RHP | 2018 | 37 | San Diego Padres |
| C.J. Abrams | GA | Blessed Trinity Catholic | 2019 | SS | 2019 | 1st | San Diego Padres |
| Juan Carlos Abreu | FL | Winter Springs | 2016 | OF | 2016 | 23 | Red Sox |
| Tyler Acosta | IL | Barrington | 2018 | OF | 2018 | 39 | Diamondbacks |
| Garrett Acton | IL | Lemont | 2016 | RHP | 2016 | 35 | White Sox |
| Cory Acton | FL | American Heritage | 2018 | 2B | 2022 | 9 | Braves |
| Joe Adametz | PA | Governor Mifflin | 2018 | LHP | 2022 | 14 | Tigers |
| Mark Adamiak | KS | Shawnee Mission Northwest | 2019 | RHP | 2022 | 15 | Athletics |
| Jesse Adams | OH | Toledo St. John's | 2012 | OF | 2016 | 14 | Reds |
| Blake Adams | AR | HarBer | 2019 | RHP | 2022 | 13 | Rockies |
| Luke Adams | IL | Hinsdale Central | 2022 | 3B | 2022 | 12 | Brewers |
| Jordyn Adams | NC | Green Hope | 2018 | OF | 2018 | 1 | Los Angeles Angels |
| Brett Adcock | MI | Bay City Western | 2013 | LHP | 2016 | 4 | Astros |
| Jordon Adell | KY | Ballard | 2017 | OF | 2017 | 1st | Angels |
| Eric Adler | FL | Rockledge | 2019 | RHP | 2022 | 6 | White Sox |
| Joe Aeilts | IL | Champaign Central | 2016 | OF | 2019 | 14 | Rockies |
| Jake Agnos | VA | Battlefield | 2016 | LHP | 2019 | 4th | Yankees |
| Zach Agnos | VA | Battlefield | 2019 | SS | 2022 | 10 | Rockies |
| Tayler Aguilar | CO | Northridge | 2019 | OF | 2022 | 15 | Yankees |
| Devan Ahart | MI | Orchard Lake St Mary's | 2010 | OF | 2015 | 16th | Dodgers |
| John Aiello | PA | Germantown Academy | 2015 | 3B | 2018 | 14 | Blue Jays |
| Max Alba | WI | Franklin | 2018 | RHP | 2018 | 39 | Angels |
| Glenn Albanese | IL | Batavia | 2017 | RHP | 2021 | 15 | Los Angeles Angels |
| Luke Albright | IN | Fishers | 2018 | RHP | 2021 | 6 | Diamondbacks |
| Mason Albright | FL | IMG Academy | 2021 | LHP | 2021 | 12 | Los Angeles Angels |
| Blaze Alexander | FL | IMG Academy | 2018 | SS | 2018 | 11th | Arizona Diamondbacks |
| A.J. Alexy | PA | Twin Valley | 2016 | RHP | 2016 | 11 | Dodgers |
| Pedro Alfonseca | MO | North Kansas City | 2016 | OF | 2017 | 17 | Indians |
| Michael Alfonso | FL | Key West | 2021 | SS | 2021 | 17 | Texas Rangers |
| Peyton Alford | TN | Powell | 2016 | LHP | 2021 | Free Agent | Seattle Mariners |
| Matthew Allan | FL | Seminole | 2019 | RHP | 2019 | 3rd | New York Mets |
| Cameron Alldred | OH | Cincinnati Country Day | 2015 | LHP | 2018 | 24th | Pittsburgh Pirates |
| Justin Alleman | MI | Holt | 2012 | RHP | 2016 | 20 | Giants |
| Austin Allen | MO | Chaminade | 2012 | C | 2015 | 4 | Padres |
| Logan Allen | FL | IMG Academy | 2015 | LHP | 2015 | 8 | Red Sox |
| Logan Allen | FL | University | 2017 | LHP | 2017 | 16 | Orioles |
| Jay Allen | FL | John Carroll Catholic | 2021 | OF | 2021 | 1C | Cincinnati Reds |
| Chris Alleyne | PA | Springside Chestnut Hill | 2017 | SS | 2022 | 19 | Dodgers |
| Nick Allgeyer | MO | Vianney | 2014 | LHP | 2018 | 12 | Blue Jays |
| Tanner Allison | MI | Portland | 2014 | OF | 2017 | 19 | Braves |
| Angelo Altavilla | MN | Lakeville North | 2015 | 3B | 2019 | FA | Diamondbacks |
| Nick Altermatt | MN | Wabasso | 2018 | SS | 2022 | 17 | White Sox |
| Nelson Alvarez | FL | Braddock | 2016 | RHP | 2016 | 27 | Indians |
| Mike Amditis | FL | Boca Raton | 2016 | C | 2016 | 37 | Indians |
| Edmond Americaan | FL | Trinity Christian Academy | 2016 | OF | 2016 | 28 | Diamondbacks |
| Cole Anderson | CO | Rocky Mountain | 2015 | OF | 2015 | 10 | Rockies |
| Ian Anderson | NY | Shenendehowa | 2016 | RHP | 2016 | 1 | Braves |
| Ben Anderson | NY | Shenendehowa | 2016 | C | 2016 | 26 | Blue Jays |
| Jack Anderson | IL | Evanston | 2012 | RHP | 2016 | 23 | Mariners |
| Ted Andrews | OH | Cincinnati Hills Christian Academy | 2012 | RHP | 2017 | 37 | White Sox |
| Tanner Andrews | IN | Tippecanoe Valley | 2014 | RHP | 2018 | 10 | Marlins |
| Isaac Anesty | ON | Our Lady Of Lourdes | 2015 | LHP | 2015 | 18 | Reds |
| Conor Angel | QC | Lakeside Academy | 2016 | RHP | 2021 | 15 | Tampa Bay Rays |
| Mack Anglin | OH | Sparta Highland | 2019 | RHP | 2022 | 7 | Royals |
| Eli Ankeney | AZ | Desert Vista | 2019 | LHP | 2022 | 20 | Mets |
| Roman Anthony | FL | Stoneman Douglas | 2022 | OF | 2022 | 2C | Red Sox |
| Oraj Anu | FL | TNXL Academy | 2017 | OF | 2017 | 28 | Red Sox |
| Ryan Aper | IL | Lincoln Community | 2011 | OF | 2013 | 6 | Marlins |
| Silas Ardoin | LA | Sam Houston | 2019 | C | 2022 | 4 | Orioles |
| Chandler Arnold | TX | Horn | 2018 | RHP | 2022 | 13 | Cardinals |
| Zach Arnold | CA | Great Oak | 2019 | SS | 2019 | 34th | Orioles |
| Jeremy Arocho | MD | Old Mill | 2017 | SS | 2017 | 27 | Dodgers |
| Aiva Arquette | HI | St. Louis | 2022 | SS | 2022 | 18 | Diamondbacks |
| Edwin Arroyo | FL | Central Pointe Christian | 2021 | SS | 2021 | 2 | Seattle Mariners |
| Aaron Ashby | MO | Park Hill | 2016 | LHP | 2018 | 4 | Brewers |
| Mason Auer | MO | Kickapoo | 2019 | RHP | 2021 | 5 | Rays |
| Myles Austin | GA | Westlake | 2019 | SS | 2019 | 20 | Milwaukee Brewers |
| Jace Avina | NV | Spanish Springs | 2021 | OF | 2021 | 14 | MIL |
| Daniel Avitia | AZ | Alhambra | 2021 | RHP | 2021 | 19 | Chicago Cubs |
| Danny Ayers | IN | Columbus North | 2013 | LHP | 2013 | 25 | Orioles |
| Cole Ayers | OH | West Clermont | 2018 | RHP | 2021 | 16 | New York Yankees |
| Carter Bach | VA | Centreville | 2016 | LHP | 2019 | 34th | Rays |
| Lake Bachar | IL | Wheaton North | 2012 | RHP | 2016 | 5 | Padres |
| Sam Bachman | IN | Hamilton Southeastern | 2018 | RHP | 2021 | 1 | Angels |
| Mahki Backstrom | CA | Serra | 2019 | 1B | 2019 | 18 | Braves |
| Dakota Bacus | IL | Moline | 2009 | RHP | 2012 | 9 | Athletics |
| Nathan Baez | AZ | Ironwood Ridge | 2019 | 2B | 2022 | 12 | Twins |
| Joshua Baez | MA | Dexter | 2021 | OF | 2021 | 2 | St. Louis Cardinals |
| Patrick Bailey | NC | Wesleyan Christian Academy | 2017 | C | 2020 | 1 | San Franciso Giants |
| Adam Bainbridge | PA | Wilson | 2013 | LHP | 2017 | 30 | Royals |
| Andrew Baker | FL | Ridge Community | 2016 | LHP | 2016 | 36 | Indians |
| Darren Baker | CA | Jesuit | 2017 | 2B | 2021 | 10 | Nationals |
| Daniel Bakst | NY | Poly Prep Country Day | 2016 | SS | 2016 | 27 | Orioles |
| Jordan Balazovic | ON | St. Martin's Collegiate SS | 2016 | RHP | 2016 | 5 | Twins |
| Thomas Balboni | FL | St John Neumann | 2019 | RHP | 2022 | 15 | Padres |
| Drake Baldwin | WI | Madison West | 2019 | C | 2022 | 3 | Braves |
| Brooks Baldwin | NC | Whiteville | 2018 | SS | 2022 | 12 | White Sox |
| Cameron Balego | PA | Pittsburgh Central Catholic | 2013 | SS | 2017 | 30 | Cubs |
| Trey Ball | IN | New Castle | 2013 | LHP | 2013 | 1 | Red Sox |
| Bryce Ball | IA | Mason City Newman Catholic | 2016 | 1B | 2019 | 24 | Braves |
| Sam Ballard | IL | Alton | 2016 | LHP | 2019 | 28 | Padres |
| Will Banfield | GA | Brookwood | 2018 | C | 2018 | Comp Bal B | Marlins |
| Caleb Baragar | MI | Jenison | 2012 | LHP | 2016 | 9 | Giants |
| Joe Baran | PA | Hazleton Area | 2015 | LHP | 2018 | 22 | Brewers |
| Colin Barber | CA | Pleasant Valley | 2019 | OF | 2019 | 4th | Astros |
| Hunter Barco | FL | Bolles | 2019 | LHP | 2022 | 2 | Pirates |
| Matthew Barefoot | NC | Midway | 2015 | OF | 2019 | 6 | Houston Astros |
| Alec Barger | IL | Champaign Central | 2016 | OF | 2019 | 17 | Braves |
