Madison Bumgarner pitched well yesterday, yet he didn't homer and the Giants lost 1-0, so really the loss was entirely his fault. And if you think it's unfair to hold him to the standard that he should homer every game he pitches, you're wrong. It's incredibly fair, and I'm going to prove it by holding all the other Giants starters to that standard as well. This is Ranking Possible Pitcher Homers.
Matt Cain is injured right now, but he will presumably be back at some point this year and take his spot in the rotation, whereupon he can get to the more important business of taking at bats. Cain has actually hit six homers in the majors, though none since 2012, so it's not like it's that unlikely that he'll hit another one. And also, he's Matt GD Cain. Matt Cain doing fun things is better than other people doing the same fun things, and he should be treated accordingly.
Likelihood of his homering this year: 7%
Enjoyment factor (1-10): 10
I have no information on Albert Suarez's ability to hit, and neither do you. He went 0-for-5 in Sacramento and is 1-for-8 with the Giants, and that is the entirety of his professional hitting experience. That would certainly make it unexpected and delightful if he hit one out, but it also makes a homer less likely. On the other hand, we don't know him that well, and Mike Leake homered for the Giants last year, which, looking back on that, eh.
Enjoyment factor: 8
Jake Peavy has actually homered as a Giant! It happened last year. Here's a highlight, because that's fun:
I was at that game, so I'd love to take credit, but let's be honest: it was all Andres Torres. Andres Torres is the greatest human being in the history of the world, and he was at the game, very close to home plate, and it seems fairly obvious that he brought just enough magic to the park that a legally blind guy could hit a homer. That being said, I don't expect Peavy to hit another one, as Torres magic is a fickle wonderbeast upon which no sane human should rely.
Enjoyment factor: 8
Samardzija's hit a couple of home runs on the year, but on the whole, his hitting career hasn't been anything special. Still, the word on the Giants broadcast is that he has some very fun BP sessions, which, if he hit one out in the game, would presumably translate into a much longer and more entertaining dinger than you could expect from most of the rest of the staff.
Enjoyment factor: 9
Johnny Cueto has never homered in his big league career. In fact, in about 8 years as a National League pitcher, he has exactly one extra base hit. So this is a steep hill to climb. But just imagine it. Close your eyes and picture a Johnny Cueto home run in your mind's eye. He swings. The ball soars. He walks out of the box. The pitcher turns. The outfielder runs back. Cueto starts quarter-heartedly jogging. Another outfielder runs to the wall. The pitcher's face falls. Cueto starts grinning, grinning like a madman, grinning like a general accepting his enemy's surrender. Everyone in the dugout is on the rail, some with eyes wide, some with jaws open, some just hopping. The ball clears the fence. The outfielders' shoulders slump. Cueto misses shaking Billy Hayes's hand, so he goes back from second base to shake it. The entire stadium is raptured into heaven. Life is complete. Life is joyous. Life has meaning.
Enjoyment factor: NINE HUNDRED MILLION