The photo of Cubs manager David Ross above says it all, I think, about playing baseball during the novel coronavirus pandemic.
Ross is setting an example by wearing a mask. (Incidentally, that’s the kind of mask I’ve been using, one you can put around your neck, then pull up to cover your nose and mouth.) MLB’s Operations Manual for 2020 (click on that link to read it, highly recommended that you do) provides for all personnel to wear masks while at ballparks:
All Tier 1, 2, and 3 Individuals must wear a face covering and, where appropriate, additional PPE at all times when in Club facilities, with the limited exceptions described in Sections 4.