With all the controversy surrounding Kris Bryant, I was wondering if there was any pattern to the call-ups to the majors this season. The following is a list of players who debuted in 2015, with their debut date and birtday:
| Player | Birthday | Debut |
| J.R. Graham | 1990-01-14 | 2015-04-06 |
| Micah Johnson | 1990-12-18 | 2015-04-06 |
| Devon Travis | 1991-02-21 | 2015-04-06 |
| Odubel Herrera | 1991-12-29 | 2015-04-06 |
| Miguel Castro | 1994-12-24 | 2015-04-06 |
| Brandon Cunniff | 1988-10-07 | 2015-04-07 |
| Cody Martin | 1989-09-04 | 2015-04-07 |
| Tyler Olson | 1989-10-02 | 2015-04-07 |
| Keone Kela | 1993-04-16 | 2015-04-07 |
| Jung-ho Kang | 1987-04-05 | 2015-04-08 |
| Allan Dykstra | 1987-05-21 | 2015-04-08 |
| Tyler Ladendorf | 1988-03-07 | 2015-04-08 |
| Mark Canha | 1989-02-15 | 2015-04-08 |
| Logan L Verrett | 1990-06-19 | 2015-04-08 |
| Angel Nesbitt | 1990-12-04 | 2015-04-08 |
| Delino Deshields Jr. | 1992-08-16 | 2015-04-08 |
| Jason Garcia | 1992-11-21 | 2015-04-08 |
| Roberto Osuna | 1995-02-07 | 2015-04-08 |
| Paulo Orlando | 1985-11-01 | 2015-04-09 |
| Asher Wojciechowski | 1988-12-21 | 2015-04-09 |
| Matt Andriese | 1989-08-28 | 2015-04-10 |
| Mikie Mahtook | 1989-11-30 | 2015-04-10 |
| Sean P Gilmartin | 1990-05-08 | 2015-04-10 |
| Matthew Tracy | 1988-11-26 | 2015-04-11 |
| Archie Bradley | 1992-08-10 | 2015-04-11 |
| Christopher Rearick | 1987-12-05 | 2015-04-12 |
| Andrew Schugel | 1989-06-27 | 2015-04-12 |
| Taylor Featherston | 1989-10-08 | 2015-04-12 |
| Raisel Iglesias | 1990-01-04 | 2015-04-12 |
| Andrew D McKirahan | 1990-02-08 | 2015-04-12 |
| Sugar Ray Marimon | 1988-09-30 | 2015-04-14 |
| Scott Oberg | 1990-03-13 | 2015-04-14 |
| Jose Miguel Urena | 1991-09-12 | 2015-04-14 |
| Rafael Martin | 1984-05-16 | 2015-04-15 |
| Branden H Pinder | 1989-01-26 | 2015-04-15 |
| Yasmany Tomas | 1990-11-14 | 2015-04-15 |
| Adam Liberatore | 1987-05-12 | 2015-04-17 |
| Daniel Muno | 1989-02-09 | 2015-04-17 |
| Felipe Rivero | 1991-07-05 | 2015-04-17 |
| Kris Bryant | 1992-01-04 | 2015-04-17 |
| Ryan D Brett | 1991-10-09 | 2015-04-18 |
| Orlando Calixte | 1992-02-03 | 2015-04-19 |
I would have expected players who debuted on or after April 17 to be younger so teams could control them for seven years. The three youngest players debuted early. Miguel Castro and Roberto Osuna are relief pitchers for the Blue Jays, both seasonal age 20. They were starters in the minors, so I suspect the Blue Jays will move them in that direction eventually. Maybe as pitchers, the Blue Jays don’t think they’ll need to pay them as much, or they are going to send them back down to the minors at some point. It seems that not all teams are sticking to the seven year model.
I know they’re subjective but it would be interesting to see when players ranked in a team’s top 10 prospects debut. I don’t think teams are quite as concerned about service time for guys lacking that “top prospect” cachet.