Think so? I have my doubts.
The Red Sox were barely treading water, if even doing that well, on June 15. They went 72-60, post trade and and made the playoffs. Devers also refused to play 1B when Casas went down.
The Giants were 10 games over .500 at the time of the trade and ended the season 81-81. Other than playing 1B when the Giants asked him to, there is virtually nothing Devers did better in his last 90 games than in the 1st 73. Further, compare that that to Roman Anthony, Devers' replacement in the lineup. In 19 less games, Anthony had only 4 less hits in 78 less ABs, more doubles, 32 less Ks, and better percentages in all three slash categories than Devers.
Offensively, Anthony's injury and subsequent absence was the backbreaker. By virtue of the tie breaker, The Red Sox held the top Wild Card spot and only 2.5 behind Toronto on September 2.