Giants vs. Diamondbacks: A Beginner’s Guide to an Upcoming MLB Series

What’s the Big Picture?

If you’re new to baseball or just catching up, here’s the story: two teams — the San Francisco Giants and the Arizona Diamondbacks — are about to play a three-game series, and their seasons have been going in completely opposite directions lately. Let’s break it all down in a way that makes sense, even if you’ve never watched a game before.

A Tale of Two Teams Going Opposite Ways

Where They Started

About a month ago, the Arizona Diamondbacks were looking pretty good. They had a record of 31-24 (31 wins, 24 losses) after sweeping the Giants — meaning they beat them in every game of their series. At that point, Arizona was:

• 10th in runs scored (pretty good hitting)
• 16th in team ERA (decent pitching — more on ERA below)

What’s ERA? ERA stands for Earned Run Average. It’s a number that tells you how many runs a pitcher allows, on average, every 9 innings (a full game). Lower is better. Think of it like a report card grade for pitchers — a 2.00 is an A+, while a 6.00 is a D.

Their star hitters were on fire:

What’s wRC+? It’s a stat that measures how good a hitter is compared to the average player. 100 is average. Anything above 100 is better than average, and anything below is worse. So 158 is really good, and 36 is really bad.

Their pitchers were led by Michael Soroka (who was having a comeback season for the ages) and Eduardo Rodriguez.

Then Everything Flipped

Since that sweep, the two teams have basically swapped places:

• Arizona: 10 wins, 18 losses (ouch)
• San Francisco: 13 wins, 14 losses (not great, but much better)

Why Is Arizona Struggling So Much?

1. The Pitching Fell Apart

Arizona’s starting rotation (the pitchers who begin the games) has been a mess. Here’s what happened:

• Michael Soroka — He was pitching amazingly (2.57 ERA in his last 4 starts) until he got hurt and had to go on the IL (Injured List — like being benched because your body needs to heal).
• Eduardo Rodriguez — His ERA looks okay (2.20 over his last 5 starts), but the advanced stats suggest he’s been lucky. His FIP (4.81) and xERA (5.33) suggest he’s really been more of an average pitcher.

What’s FIP and xERA? These are stats that try to figure out how a pitcher should be performing, regardless of luck or how well their fielders play. If your ERA is way lower than your FIP, you might be getting lucky — and luck doesn’t last forever.

• Ryne Nelson, Merrill Kelly, and Zac Gallen — These three have been terrible. Combined, they’ve given up a lot of runs in 89 innings (16 starts together) with a combined ERA of 7.08. That’s really, really bad.

2. The Hitting Got Cold

Arizona’s offense has scored the second-fewest runs in all of baseball over the last 30 days (only 95 runs — barely more than 3 per game). Their best hitters have cooled off significantly:

What About the Giants?

Their Offense Is Legit

Even though the Giants have had some big wins, they’ve scored 133 runs since May 28th, which ranks only 15th in baseball. But here’s the thing — analytically (using advanced stats), they’ve been the best offense in baseball with a 126 wRC+ (1st in MLB).

Compare that to Arizona’s 80 wRC+ over the same period, and the Giants’ hitting looks like a powerhouse against Arizona’s struggles.

The only Giants who haven’t been hitting well lately:

• Willy Adames (93 wRC+ — just below average)
• Daniel Susac (47 wRC+)
• Drew Cavanaugh (42 wRC+)
• Eric Haase (28 wRC+)
• Buddy Kennedy (-53 wRC+ — and he was traded to the Mariners, so he’s not even on the team anymore)

Their Pitching Has Some Concerns

The Giants have two great starters in Logan Webb and Robbie Ray, but after those two, the pitching staff is really easy to hit. Over the last 30 days:

• Team ERA: 4.51 (21st in MLB — below average)
• fWAR: +1.7 (20th in MLB)

What’s fWAR? It stands for Fan Wins Above Replacement. It tells you how many extra wins a player (or team) has contributed compared to a replacement-level player (someone you could find easily). Higher is better.

One interesting note: the Giants have historically been one of the best groundball teams in baseball (44.4% groundball rate, 5th best in MLB). But over the last month, that number has dropped to 40.2% (19th). Groundballs are good because they rarely become home runs. The article suggests this might just be a temporary blip, especially with Logan Webb on the IL.

Fun fact: Since groundball data started being recorded in 2002, the Giants have had a groundball rate below 42% only twice — in 2008 and 2020.

Series Details

Projected Starting Pitchers

Players to Watch

For the Diamondbacks

• Geraldo Perdomo — Last year’s breakout star has been heating up lately, hitting well over his last 28 games (.805 OPS). He had a great weekend series against the Rays (6 hits in 11 at-bats with a double and a home run). However, he’s been weaker at home and is only 5-for-22 against the Giants this season.

• Paul Sewald & Kevin Ginkel — These are Arizona’s relief pitchers (pitchers who come in after the starter). The overall bullpen has been bad in June (5.00 ERA), but these two have been excellent:

  • Ginkel: 2-0 with a 2.16 ERA in June (though his FIP of 5.98 suggests some luck)
  • Sewald: 1-0 with 4 saves in June, with a solid 3.23 FIP

  What’s a save? When a relief pitcher finishes a game and protects a narrow lead (usually 3 runs or fewer), they get a "save." It’s like being the closer — the last line of defense.

For the Giants

• LuJames Groover — Okay, he might not be a superstar, but that name is incredible. The article’s author compares it to MacGrover. Groover was drafted in 2023 and is known for being very patient at the plate (.392 OBP in the minors).

  What’s OBP? On-Base Percentage. It measures how often a player reaches base. .392 is really good — it means he gets on base almost 40% of the time.

• Bryce Eldridge — A potentially great hitter facing a struggling pitching staff. This could be a fun matchup.

• Heliot Ramos — A power-hitting middle-of-the-order guy coming back from injury, facing that same bad pitching staff. Could be dangerous.

• Landen Roupp — The Giants’ Tuesday starter has lost his last 10 starts (0-6 with a 5.12 ERA). The Giants have lost every single one of those games (0-10). That’s rough.

• Pavin Smith & Tommy Troy — The article predicts these two will "annoy the Giants at least once" during the series. Sometimes players just have a knack for making things happen.

So, Who’s Going to Win?

Here’s the honest answer: it’s complicated.

On paper, the Giants have the better offense right now, and Arizona’s pitching is a mess. But baseball isn’t played on paper. The Giants’ starter Landen Roupp can’t seem to win a game, and Arizona has dominated the Giants this season (6-0 record with a +22 run differential).

What’s run differential? It’s the difference between the runs a team scores and the runs they allow. +22 means the Giants scored 22 more runs than the Diamondbacks in their 6 head-to-head wins. That’s a lot — it means those weren’t close games.

The series should be competitive, especially if the Giants’ recent improvement is real and Arizona continues to struggle.

Summary

• Arizona was playing great a month ago but has since collapsed, with both their pitching and hitting falling off dramatically.
• San Francisco has been playing better recently and has the best offense in baseball over the last 30 days by advanced metrics.
• Arizona’s rotation is in rough shape, especially with Soroka on the IL and three starters performing among the worst in baseball.
• The Giants’ offense is legit, but their pitching outside of Logan Webb and Robbie Ray is vulnerable.
• The series takes place Monday through Wednesday at Chase Field in Phoenix.
• Arizona has dominated the Giants this season (6-0), but the teams are trending in opposite directions.

FAQ

Q: What does "sweeping" a series mean?
A: It means winning every game in that particular series. If two teams play three games and one team wins all three, that’s a sweep.

Q: Why should I care about FIP and xERA if ERA already exists?
A: Great question! ERA tells you what actually happened, but FIP and xERA try to predict what should have happened by focusing on things the pitcher can control (strikeouts, walks, home runs) and removing the influence of defense and luck. If there’s a big gap between ERA and FIP, it’s a sign that the pitcher might not be as good (or as bad) as they seem.

Q: What does "wRC+" actually mean in plain English?
A: It’s a way to measure how good a hitter is compared to the average major leaguer. 100 is exactly average. Every point above 100 means they’re 1% better than average. So 120 is 20% better than average, and 50 is 50% worse than average.

Q: Why are the Giants’ groundball numbers important?
A: Groundballs are the safest type of batted ball. They almost never become home runs and rarely go for extra bases. Teams that hit a lot of groundballs tend to give up fewer big innings. The Giants have historically been great at this, so the recent drop-off is a concern.

Q: Is this series likely to be on national TV?
A: No. The article notes there are no national broadcasts for this series, so you’d need to check your local sports network to watch.