“There’s still work to do,” manager Alex Cora said before Boston’s game against the Astros on Friday. “He’s still a work in progress. He’s gotten better. The numbers show that. There’s a few things under the hood that we still need to get better at.” Cora said there are areas, both offensively and defensively, where he must improve.

Campbell started the season at second base and joined a rotating cast of Red Sox candidates learning to play first base after the season-ending knee injury to Triston Casas. That work continues in Worcester, with Campbell feeling better about his ability to impact the game with his glove.

If the Red Sox want to add a top talent before Thursday's trade deadline, Boston might have to give up a top prospect or two.