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Series Preview # 16 : Diamondbacks vs Giants

Diamondbacks chances in this series are better than it might seem at first glance because the Giants bullpen is weak.

Ketel Marte is back from the IL.
Ketel Marte is back from the IL.
Photo by Harry How/Getty Images

As recently as a week ago, before injuries and the batting slump, the Diamondbacks had scored more runs per game than the Giants. Injuries matter.

To see the whole picture, we need to look at which team is older, who are the above-average players for this series, and compare the impact of injuries on the teams.

Which team is older?

The Giants are older than the Diamondbacks. In games played through 17 May, the comparisons of average ages follow:

  • Starters (IP weighted averages): Giants 29.4 vs D-backs 28.5.
  • Relievers (IP weighted averages): Giants 29.0 vs D-backs 28.4.
  • Position Players (PA weighted averages): Giants 31.3 vs D-backs 29.6.

What is an average Player?

Wins Above Replacement (WAR). Per the FanGraph’s glossary, WAR estimates the value that would be lost if a player was replaced by either a minor league player or a AAAA player from the team’s bench.

Demarcation Line for Average Player. The FanGraph’s glossary defines an average player as follows:

  • 2 WAR for position player.
  • 2 WAR for starting pitcher.
  • 0-1 WAR for bench player.
  • < 1 WAR for relief pitcher.

Who are the above-average players for this series?

This season, for the Giants and Diamondbacks, how many players do I expect to contribute at least 2 WAR? In games through 17 May, any player whose WAR (Baseball Reference) was at least 0.5 was on-pace for a 2 WAR season. In addition, I added Nick Ahmed, who in last season’s 60 game season accumulated 1.9 WAR (and this season he is less due to a batting slump). Tyler Rogers is an extraordinary reliever who I expect to exceed 2 WAR. The following table shows players who I expect to be above average, with my projected WAR for the season.

2021 WAR projected on 17 May. Data from Baseball Reference.

The Giants have 14 above-average players while the Diamondbacks have 10. Injuries had a much greater impact on the Diamondbacks, reducing their above-average players by 40%.

  • Giants: None of their 9 position players with 2+ WAR is on the IL, although Solano recently returned from the IL. One of the 5 pitchers with 2+ WAR is on the IL.
  • Diamondbacks: Two of the 7 position players with 2+ WAR is on the IL (It would have been 3 except Ketel Marte recently returned from the IL). Two of the 3 pitchers with 2+ WAR is on the IL. TWO UPDATES: Taylor Widener returned from the IL to start Sunday’s game. It appeared he was again injured when he left the game after two outs in the second inning. Carson Kelly was reinstated to play in Tuesdays’ game. Despite the reinstatement I’m confident that his broken big toe remains a significant injury because bones take much longer than 10 days to heal.

Remarkably, the Giants have significantly fewer above-average players on the IL despite being older than the Diamondbacks. Injury prevention matters.

How much better is the Giants rotation compared to last season?

The Giants rotation is 5.3 wins better than last season. This season they rank second in the Majors, when last season they ranked 27th (WAA in Baseball Reference). The reason this happened is all four of their above-average starters were acquired (or re-acquired) this offseason.

Experience matters. The Giants’ rotation is experienced. The ages of their five above-average pitchers are 31, 30, 30, 30, and 28(will be 29 on 1 July).

Neil Paine wrote, “With that, the Giants are also the first team since the 2014 Phillies with an average age over 30 for both their batters and pitchers.” My opinion differs slightly. When the average is weighted by innings pitched in games through 17 May, I found that their starters averaged 29.4 years old, and relievers averaged 29.0 years old. Nevertheless, those average ages are older than the Diamondbacks pitchers’ averages (28.5 and 28.4 years old).

How weak is the Giants bullpen?

The Giants bullpen has a WAR of negative 1.0, which ranks last in WAR (FanGraphs). They have 12 blown saves. The bullpen was awarded 11 losses, while starters were awarded 8 losses.

The Diamondbacks’ chances in this series are better than it might seem at first glance because the Giants bullpen is weak. In this two game series, who starts will likely determine whether the weakness in the Giants’ bullpen allows the Diamondbacks to score the winning runs. Let’s look at the possible matchups.

Pitching Matchups

Tuesday. Kevin Gausman (1.66 ERA) vs TBA, possibly Corbin Martin (5.40 ERA).

The Giants won 8 of the 9 games which Kevin Gausman started. In the three games they lost, he pitched 22.2 innings with 3 ERs. In one game which the Giants won, he allowed 5 ERs against the Reds - so he is human.

On 18 May, Corbin Martin pitched 5 innings with 3 ERs. Six Dodgers reached base (4 walks and 2 singles); 5 were stranded and did not score. He allowed 2 homers; his worst moment was when Chris Taylor hit a two-run homer in the fifth inning.

In James Attwoods’ player preview he wrote that although the sample size is small, walks could be an issue for Corbin. My prediction is Corbin Martin will likely keep the game close to give the Diamondbacks winning chances.

This matchup is a small advantage Giants.

Wednesday. Johnny Cueto (3.34 ERA) vs TBA, possibly Merrill Kelly (5.05 ERA).

This season, Johnny Cueto injured his latissimus dorsi muscle (lats). Before the injury his ERA was 1.80. After the injury, his ERA was 8.59.

In May, Merrill Kelly’s ERA is 3.65, an improvement from April. In his last seven starts his game scores were average or above; two game scores were above 60! In his last start against the Dodgers, he struck out 12 batters while walking none. His solid performance earned him spot in the rotation.

Recently Merrill Kelly has pitched better than Johnny Cueto. Because the weak Giants’ bullpen, this game is an opportunity for the Diamondbacks to win!