It could be a sign that Jackie Bradley Jr. is not impressing the Red Sox brass, and the Sox are looking for a spark, possibly from Mookie Betts, as their season is spiraling downward.
Bradley Jr. is hitting .200/.301/.296 with a 16/42 BB/K ratio, and a K-rate of 33.6%. If Boston had better options, Bradley would be in AAA right now. Unfortunately, none of Nava, Brentz, or Hassan are impressing. Betts in CF is a sign Boston will be calling him up soon because of their continued struggles in the OF in both AAA and the majors.