Here are my votes. I didn’t include anyone with less than 50 PA or 15 IP.
Exceeding expectations
Henderson .892 OPS, 2.7 rWAR
Westburg .871 OPS, 1.8 rWAR
Cowser .831 OPS, 0.7 rWAR (ignoring recency bias)
O’Hearn .883 OPS, 1.0 rWAR
Mateo .706 OPS, 0.6 rWAR
Irvin 4-1, 2.90 ERA, 0.9 rWAR
Suarez 2-0, 1.96 ERA, 0.8 rWAR
Webb 0-2, 1.47 ERA, 0.4 rWAR
Akin 1-0, 3.00 ERA, 0.2 rWAR
Coulombe, 0-0, 2.30 ERA, 0.5 rWAR
Meeting expectations
Rutschman .834 OPS, 1.7 rWAR
Mountcastle .797 OPS, 1.2 rWAR
Santander .731 OPS, 0.5 rWAR
McCann .541 OPS, - 0.5 rWAR
Burnes 3-2, 2.68 ERA, 1.0 rWAR
Kremer 3-3, 3.73 ERA, -0.2 rWAR
Rodriguez 4-1, 3.71 ERA, 0.3 rWAR
Cano 2-1, 2.21 ERA, 0.4 rWAR
Baumann 1-0, 4.02 ERA, -0.1 rWAR
Failing to meet expectations
Mullins .592 OPS, 0.4 rWAR
Urias .492 OPS, 0.0 rWAR
Hays .311 OPS, -0.9 rWAR
Wells 0-2, 5.87 ERA, -0.3 rWAR
Kimbrel 4-1, 3.86 ERA, 8 saves, 3 blown saves, 0.0 rWAR
Obviously, many of these are debatable, and largely depend what your expectations were to begin with. For example, Adley is having an excellent season, but I expect excellence from him. He’s probably exceeding my expectations a little, but not enough to put him in the exceeding expectations category. My expectations for Baumann were low, and he’s doing about what I expected.
Bottom line, we have more guys exceeding expectations than failing to meet them, but there’s plenty of room for improvement