The Diamondbacks are much better against righties than southpaws going 13-8 versus righties as opposed to 0-7 against lefties.
Righty Trevor Cahill will be making his third start replacing injured Jeff Samardzija. He's failed to go more than four innings in either of his starts. The Giants need their starters to go deep into games because their bullpen is so vulnerable. 
Cahill is 0-2 with a 5.09 ERA in seven career appearances against the Diamondbacks. 
Luke Weaver was emerging into a star before he was injured. The buy sign is back on Weaver as he rounds into shape. He's coming off his best start giving up one run on three hits in five innings in a 10-1 victory against the A's this past Tuesday. Weaver is 3-1 with a 1.99 ERA in four career starts against the Giants.