There shouldn't be a "but" in that second sentence. There are many precedents to DeJong's number here, both in a ~29-game stretch and in the first ~29 games of a season; but again, in the past 83 years, there is no precendent for even 60 in a season.
DeJong's double count through the Cardinals' first 29 puts him on level with Matt Carpenter, who did the same thing in 2015. He finished with 44 doubles in 154 games--or 30 in the remainder. That was a great season, too.
In just the 2010s, DeJong's '14 in a calendar month' has been matched by 14 other players, usually in fewer games.
| Player | Month | G (month) | 2B (month) | G (Season) | 2B (Season) |
|---|---|---|---|---|---|
| Devon Travis | May 2017 | 26 | 16 | 50 | 18 |
| Jose Altuve | Sep/Oct 2015 | 30 | 16 | 154 | 40 |
| Jose Abreu | May 2018 | 27 | 15 | 128 | 38 |
| Chris Coghlan | Jun 2010 | 26 | 15 | 91 | 20 |
| Albert Pujols | Sep/Oct 2010 | 29 | 15 | 159 | 39 |
| Fred Lewis | May 2010 | 26 | 15 | 110 | 31 |
| Jason Kipnis | May 2015 | 29 | 15 | 141 | 43 |
| Joey Wendle | Sep/Oct 2018 | 25 | 14 | 139 | 33 |
| Paul DeJong | Mar/Apr 2019 | 29 | 14 | ?? | ?? |
| Asdrubal Cabrera | May 2013 | 29 | 14 | 136 | 35 |
| Eduardo Escobar | Jun 2018 | 27 | 14 | 151 | 48 |
| Christian Yelich | Sep/Oct 2015 | 30 | 14 | 126 | 30 |
| Manny Machado | May 2013 | 28 | 14 | 156 | 51 |
| Daniel Murphy | Jul 2011 | 27 | 14 | 109 | 28 |
| Alexei Ramirez | May 2011 | 29 | 14 | 158 | 31 |
Source: Baseball-Reference