Hand is 5-5 with a 3.59 ERA and 21 saves this season.
Hand signed a one-year, $10.5 million contract with the Nats this past offseason. He was coming off another solid season as the closer for the Cleveland Indians in 2020, leading the major leagues with 16 saves, but was a victim of the team's salary purge heading into 2021.
The Blue Jays have had a multitude of injuries in their bullpen, beginning with the team losing Kirby Yates to Tommy John surgery to start the season.
Adams, 25, is considered the best power hitter in Toronto's system according to Baseball America. He joins the Nationals after hitting .239 with seven homers, 17 RBIs in 35 games for Triple-A East Buffalo.