Agree with Larnach, Ober and Jeffers, but looking at who's on the IL right now, it is amazing the team has remained in contention at all:
Jeffers, Kirilloff, Larnach - Expected starting position players
Sano, Garlick - Expected bench contributors
Ober, Paddack, Dobnak - Expected starting rotation
Stashak, Coulombe, Alcala, Romero - Bullpen arms
Maeda, Lewis - September reinforcements
Buxton, Kepler - Walking wounded
Correa (120 OPS+) and Polanco (118 OPS+) are not underperforming, they just seem to fail in big spots when the team needs them.