None of that is a secret, which is why Boston is priced as a heavy favorite here. But the Red Sox aren't walking in fully healthy either, and that's worth sitting with before treating this as a formality.
Willson Contreras is still working back from a hamstring issue, Ceddanne Rafaela is out with a quad strain, and Masataka Yoshida's hamstring injury has him shelved for the stretch run. Adley Rutschman got a cortisone shot in his throwing elbow this week and is day-to-day. That's four semi-regular bats missing from a lineup that's supposed to be doing the heavy lifting behind Gray.
Kansas City has actually won its last game, part of a stretch where it's gone 2-3 over its last 5, including taking 1 of the first 3 from Arizona. Boston's been the better team overall this year but walks in having lost 2 straight, following a stretch where it took 2 straight from Baltimore.