I don't see it posted by Rock. I did some checking and the best pitcher of the day is

TED LILLY vs. COLORADO
LILLY is 6-2 when starting against COLORADO with an ERA of 4.21 and a WHIP of 1.247.
His team's record is 7-2 (+5.7 units) in these starts. The OVER is 5-4. (+1.1 units)

Lilly is a +4, there are 4 others that are +3. This is using Rockdemansports criteria.

JOHN DANKS vs. OAKLAND
DANKS is 4-1 when starting against OAKLAND with an ERA of 2.25 and a WHIP of 1.229.
His team's record is 4-3 (+0.0 units) in these starts. The UNDER is 3-3. (-0.1 units)

MAX SCHERZER vs. SEATTLE since
SCHERZER is 3-0 when starting against SEATTLE with an ERA of 2.25 and a WHIP of 1.100.
His team's record is 3-0 (+3.0 units) in these starts. The OVER is 1-2. (-1.3 units)

DAVID PRICE vs. BALTIMORE
PRICE is 4-1 when starting against BALTIMORE with an ERA of 2.52 and a WHIP of 1.119.
His team's record is 5-1 (+3.3 units) in these starts. The OVER is 2-4. (-2.1 units)

CLIFF LEE vs. CHICAGO CUBS
LEE is 3-0 when starting against CHICAGO CUBS with an ERA of 1.71 and a WHIP of 1.137.
His team's record is 3-1 (+2.0 units) in these starts. The OVER is 2-2. (-0.2 units)

Just providing Info, what you do with it is up to you