Arizona has been underachieving and Luke Weaver is on the comeback trail.
But I see a buy sign on both of them today. 
The Diamondbacks halted an eight-game losing streak beating the Giants, 7-4, on Friday. That should stop the Diamondbacks from pressing and raise their confidence level.
Weaver was on track to become one of the better young pitchers in baseball before an injury derailed him. But he's looked good in his last two starts posting a 2.53 ERA. 
Journeyman righthander Trevor Cahill goes for San Francisco. Cahill is pitching well above his norm with a 1.64 ERA after three starts. The Diamondbacks hit righties much better than lefties and Cahill is due for major regression. If Cahill was anywhere close to being this good, he wouldn't be on his eighth big league team.
The Giants have lost six of the past seven times following a loss. The Diamondbacks usually do the job as home chalk winning 16 of the last 21 times in that role.