What-Have-You-Done-For-Me-Lately: starring Duvall as the hero, Yoshida as the zero. But with a month to go, they're about even for season contributions.
Sure, Duvall has the edge in WAR, but there's no guarantee he'd post positive if he played the entire season. On bb-ref, his career high is 3.3, all the way back in 2016 (bb-ref describes a player at 5+ as "All-Star Quality" and 2+ as a "Starter"). My issue with Duvall isn't so much the player, but Bloom acquiring him to be the centerfielder, where he isn't as good as at the corners, and as we've seen, takes a beating trying to cover ground. Give Duvall credit for all-out effort, but when a guy is on the IL, he's not contributing; though it's not his fault he's out of position.
Yoshida has three Es in left, but usually makes the plays he can get to. He has less range than Duvall, who has also missed some plays that other more fleet natural centerfielders make in the majors. Yoshida has a 12% K rate to Duvall's 28%, but has been hurt by a power outage the past month. Still, a guy who was leading the league in batting average during the first half obviously has to be consistent at making contact.
If grading, I probably wouldn't give either higher than a C+ because both have had to miss a lot of games for various issues. But I'd like to see if a healthy Duvall can stay hot for an entire year. I also think Yoshida will be a more productive player, at least on offense, next season after the adjustments from this initial campaign in a foreign land.