Me, I'm fine with Devers at 3B, especially when the Sox have given up just 5 unearned runs this year. I have already seen improvement in his throws to 1B, and he has also made some nice plays on weak grounders where he had to go fast and hard to get the ball and then make a good throw.
Nunez, on the other hand, gets almost no errors because he has so little range and to me is a bigger liability at 2b than Devers at 3b.
Besides, who gives a darn about errors when the real issue in 2018 is the rapid deterioration in Red Sox pitching?
In the first 19 games when the Sox went 17-2, they gave up 53 runs in 19 games, including 7 extra innings. In the most recent 12 games the Sox have given up 65 runs--roughly twice as many runs per game. We are now losing more games by 4 or more runs than we are winning by 4 or more runs.
And right now the rotation and bullpen are equally bad--or so I think without having looking up the numbers.