Here are the overall Wins Above Replacement leaders (per Baseball-Reference) at each spot on the diamond. You can also find position-by-position leaders for home runs, hits, RBIs and stolen bases.

For the purposes of this story, a player must have played at least two-thirds of his games at a position in order to qualify as its leader. Any player who played at least two-thirds of his career in the outfield (regardless of the specific outfield position) qualified in the outfield spot at which he played the most.

Catcher: Johnny Bench, 75.1
A two-time National League MVP, 14-time All-Star and 10-time Gold Glove Award winner, Bench was the total package behind the plate, combining elite defense with a potent bat. The long-time Reds backstop recorded at least 4.0 WAR in 12 seasons, including a career-high 8.6 in 1972, his second MVP campaign. He holds the WAR lead among catchers over fellow Hall of Famer Gary Carter (70.1).
Active leader: J.T. Realmuto, 36.4

First base: Lou Gehrig, 113.7
Gehrig has a sizable advantage over Albert Pujols (101.5 WAR) for the first-base WAR lead, as he averaged 8.8 WAR per season from 1926-37. To put that into perspective, Baseball-Reference considers a single-season WAR total of 8.0 or higher to be MVP caliber. Gehrig had 11.8 WAR in 1927 -- the first of his two MVP seasons -- hitting .373/.474/.765 with 47 home runs, 52 doubles, 18 triples and 173 RBIs.
Active leader: Paul Goldschmidt, 62.8

Second base: Rogers Hornsby, 127.3
Hornsby led the NL in batting average, on-base percentage and slugging percentage for six straight years from 1920-25, hitting a collective .397/.467/.666 and racking up 59.6 WAR. That stretch doesn’t even account for half of his career WAR total. Hornsby also had 9.9 WAR in 1917, 10.2 in ‘27 and 10.4 in ‘29, and he finished with the 12th-most WAR in big league history. He just edges out Eddie Collins (124.4) on the all-time list.
Active leader: Jose Altuve, 52.8

Third base: Mike Schmidt, 106.9
Schmidt is best known for his top-tier power, but he also provided excellent defense at the hot corner for years and was recognized with 10 Gold Glove Awards. Overall, Schmidt posted 5.0 WAR or better in 14 straight years from 1974-87. The Phillies' legend won three NL MVP Awards, but his highest WAR mark (9.7) actually came in 1974, a year he finished sixth in the voting. Eddie Mathews (96.1) is second on the all-time list.
Active leader: Manny Machado, 57.9

Shortstop: Honus Wagner, 130.8
An eight-time batting champion, Wagner ranks 10th on the all-time WAR list and is the shortstop leader by a wide margin over Cal Ripken Jr. (95.9). Wagner topped the NL in WAR 11 times in 13 years from 1900-12, with a personal best of 11.5 in ‘08. In 1914, a 40-year-old Wagner recorded his 3,000th hit, becoming the second player in big league history to join the club after Cap Anson.
Active leader: Francisco Lindor, 49.5

Left field: Barry Bonds, 162.7
In addition to holding the all-time records for home runs (762) and walks (2,558), Bonds is tied with Babe Ruth for the most career WAR accrued as a position player. The next closest left fielder is Ted Williams with 122.1 WAR. Bonds had 12 seasons with at least 8.0 WAR, and his 43.4 WAR from 2001-04 was 10.3 wins higher than anyone else’s total in that span.
Active leader: Christian Yelich, 41.9

Center field: Willie Mays, 156.1
A superstar in every phase of the game, Mays produced 10 or more WAR in six seasons, tying him with Hornsby for the second most in history among position players. The center fielder’s career high of 11.2 WAR came at age 34 in 1965, the year he won his second career MVP Award with a .317/.398/.645 slash line and 52 homers. Ty Cobb (151.4) is second on the all-time list.
Active leader: Mike Trout, 86.2

Right field: Babe Ruth, 182.5
Ruth is tied with Bonds for the all-time WAR record among position players, but that doesn’t take into account the Great Bambino’s contributions as a pitcher. Ruth also posted 20.4 WAR on the mound, giving him a career total of 183.1 WAR -- by far the most in history. Ruth reached the 10 WAR mark nine times as a position player and had more than 12 WAR in 1921 (12.8), ‘23 (14.1) and ‘27 (12.5).
Active leader: Mookie Betts, 69.5

Designated hitter: Edgar Martinez, 68.4
David Ortiz may be the all-time DH leader in homers, hits and RBIs, but Martinez has him beat in WAR, 68.4 to 55.3. Martinez finished his career with a .312/.418/.515 slash line, making him one of an elite group of players in the .300/.400/.500 club. His greatest WAR total (7.0) came in 1995, when he hit .356/.479/.628 with 29 homers, 52 doubles and 113 RBIs.
Active leader: Shohei Ohtani, 28.7 (also has 15.1 WAR as a pitcher)

Pitcher: Walter Johnson, 164.8
Based on pitching production alone, Cy Young is the all-time leader among hurlers with 165.6 WAR, while Johnson ranks second with 152.1. But Johnson added significant value with his bat as well, posting 12.8 WAR as a hitter. Young, meanwhile, had negative WAR as a hitter, knocking his career WAR total below Johnson’s. The Big Train was responsible for the highest single-season WAR mark of any player in the Modern Era, recording 16.5 WAR in 1913 (1.14 ERA in 346 innings).
Active leader: Justin Verlander, 80.5