DeJong, 31, was a fourth-round pick by the Cardinals back in 2015 and rose through the minors quickly to make his big league debut in 2017 at the age of 23.
DeJong looked quite good in his first season in the majors, slashing .285/.325/.532 (123 wRC+) and clubbing 25 homers in just 108 games while splitting time between shortstop and second base.
DeJong finished second in NL Rookie of the Year voting to Cody Bellinger that year, and by the time 2018 rolled around he had established himself as the Cardinals' everyday shortstop.
Following seven partial seasons in St. Louis and an All-Star in 2019, the long-time Cardinal was acquired by the Blue Jays via trade on Aug. 1 2023, one day before his 30th birthday.
His arrival also came less than 24 hours after Bo Bichette suffered a knee injury that, at the time, appeared significant.
DeJong was notably ineffective, as he went 3-for-44 (.068 AVG) with 18 strikeouts and zero walks over 13 games.
Eventually, Blue Jays brass had seen enough, designating him for assignment upon Bichette's return from the 10-day IL on Aug. 19 - ending DeJong's Blue Jays tenure after just 18 days.
DeJong redeemed himself somewhat when he hit .227 with 24 homers and 56 RBIs last year for the Chicago White Sox and Kansas City, which acquired him on July 30.
He has a .229 average with 140 homers and 400 RBIs in eight seasons with St. Louis (2017-23), Toronto (2023), San Francisco (2023), the White Sox and Royals.
The Nationals announced the agreement Sunday. Right-hander Josiah Gray was placed on the 60-day injured list.
The signing should significantly raise the floor for the Nationals on the infield, offering the club a solid defender at third base who has enough pop in his bat to provide 20 homers a year in spite of below-average on-base ability.
That's an undeniably useful player for a Nationals club that saw its third basemen finish third from the bottom in both wRC+ (67) and fWAR (-0.4) last year.