No, Baker Mayfield is not playing in Week 4. He dislocated his right thumb (throwing hand) in Week 3 against Minnesota. While the MRI showed no ligament damage, head coach Todd Bowles gave a three-week absence timeline, and injury experts put recovery at 3–6 weeks for full throwing strength. Week 4 is just one week post-injury, so he's out. Tampa Bay is expected to turn to undrafted rookie Jalon Daniels or possibly re-sign Jake Browning as the fill-in starter (from the Baker Mayfield page).
On The Fantasy Headliners, the Week 4 QB breakdown said flatly: "This is not Baker Mayfield" — .