The NL Cy Young Award race appears to be a four-man battle: the Braves' Spencer Strider vs. the D-backs' Zac Gallen vs. the Padres' Blake Snell vs. the Cubs' Justin Steele.

But one of baseball's best second-half pitchers is threatening to make it a five-way competition.

Phillies right-hander Zack Wheeler has become an NL Cy Young dark horse with his performance since the All-Star break, recording a 2.68 ERA with a 0.86 WHIP and a 7.0 K/BB ratio (56 K's, 8 BB's) over 53 2/3 innings.

Scheduled to start Friday against the Brewers, the 33-year-old may seem like a newcomer to the Cy Young conversation considering the way his first half played out. The righty had an ERA over 4.00 for much of the first half, including 4.05 after his final outing before the break.

But really, Wheeler has been here all year.

And if we set ERA aside and look at some of the other available tools we have to evaluate pitchers, his season begins to look a lot different.

In fact, FanGraphs’ version of WAR, which is based on fielding independent pitching, a metric that focuses solely on events over which a pitcher has the most control (strikeouts, walks, homers, hit batsmen), views Wheeler as MLB’s top arm. He’s 0.6 fWAR ahead of every other NL pitcher.

All stats below are through Wednesday's games.

NL fWAR pitcher rankings, 2023

1. Zack Wheeler (PHI): 5.2
2. Spencer Strider (ATL): 4.6
3. Zac Gallen (AZ): 4.0
4. Justin Steele (CHC): 3.9
5. Logan Webb (SF): 3.8

Wheeler’s place atop the rankings isn’t a new development. He was there at the end of July. He was there at the end of June. In fact, he hasn’t ranked lower than third at the end of any calendar month in 2023.

Wheeler’s NL fWAR ranks by month:

• Through April: T-3rd
• Through May: 2nd
• Through June: T-1st
• Through July: 1st
• Through August: 1st

So why was Wheeler’s ERA so high before the All-Star break? It was due to a combination of factors.

• Poor defensive support: The Phillies’ defense has improved considerably this season, recording -2 outs above average after finishing 29th in the Majors with -34 OAA a year ago, but the club’s fielding hasn’t done a lot to help Wheeler in 2023. The Phillies’ defense has cost Wheeler five runs this season, tied for the 12th most of any pitcher. That said, he’s gotten more support lately -- the Phils’ defense has saved two runs while posting +2 OAA behind him in August.

• Bad luck on balls in play: Wheeler’s career batting average on balls in play is .297, and it was even lower than that across 2021-22 (.287). However, his BABIP ballooned to .328 in the first half of 2023. Some of this was related to Philadelphia’s defense, while some was just plain bad luck. Wheeler’s fortune has turned in the second half, though: He’s notched a .233 BABIP, lowering his season mark to .298.

• Unfortunate sequencing: Wheeler’s poor batted-ball fortune came at the worst possible times in the first half. While his BABIP before the break was actually fairly normal (.308) with the bases empty, he had a .352 BABIP with runners on base. As a result, he stranded just 67.6% of his baserunners in that span, this despite allowing no home runs with runners on. Wheeler’s strand rate has jumped to 83.3% in the second half and is up to 71.3% on the year, moving closer to his lifetime 74% mark.

Again, FIP strips away the above factors, over which pitchers have little or no control. Wheeler currently has the fourth-best FIP (3.01) among qualifying pitchers behind Strider (2.79), Kevin Gausman (2.83) and Sonny Gray (2.83).

But Wheeler’s Cy Young case isn’t entirely tied to his FIP. He stacks up well against Strider, Gallen, Snell and Steele in a number of other notable categories.

Innings
Gallen: 173 1/3 in 28 starts (6.2 IP/GS)
Wheeler: 158 in 26 starts (6.1 IP/GS)
Strider: 153 1/3 in 26 starts (5.9 IP/GS)
Snell: 149 in 27 starts (5.5 IP/GS)
Steele: 144 in 25 starts (5.8 IP/GS)

Strikeouts
Strider: 236 (13.9 K/9)
Snell: 193 (11.7 K/9)
Gallen: 182 (9.5 K/9)
Wheeler: 175 (10.0 K/9)
Steele: 141 (8.8 K/9)

WHIP
Strider: 1.06
Wheeler: 1.08
Gallen: 1.10
Steele: 1.17
Snell: 1.26

K/BB
Wheeler: 5.83
Strider: 5.02
Gallen: 4.92
Steele: 4.55
Snell: 2.27

The one area he doesn’t? ERA. He’s at 3.59, nearly a full run higher than Snell’s 2.60 and Steele’s 2.69. He’s also behind Gallen (3.32) and Strider (3.46).

For as great as his other stats are, Wheeler will likely need to lower his ERA to earn serious Cy Young consideration. The last pitcher with an ERA over 3.50 to win the Cy Young was Roger Clemens (3.51) in 2001, during an era when pitcher wins (Clemens went 20-3) still had a sizable influence in the voting.

The Phillies ace has a month left to get it done.