With the rules and schedules finally stabilized, the 1900s began the modern era of baseball. The American League was able to establish themselves as a competitive "major league" in 1901, creating the still-standing basis of the MLB. The Pirates dominated the early part of the decade, and the Cubs and Tigers dominated the end. Every pitcher and all but two position players selected are in the Hall of Fame.
C- Roger Bresnahan
More known as the inventor of shin guards and facemask padding, Bresnahan also was the best catcher of the decade. He used his .385 OBP to amass over 30 WAR, even though he started the decade as a pitcher and in the minors. Johnny Kling was the only other catcher to come close to 20 WAR. Bill Bergen gets a dishonorable mention, somehow staying in the majors despite being 10+ wins below replacement in the decade.
1B- Frank Chance
The ending to the famous poem, Chance provided about 45 WAR to the Cubs in the decade. He was a good hitter, but his main skills were drawing walks, playing great defense, and stealing the second-most bases in the decade. Harry Davis produced about 35 WAR for the A's, the only player near Chance.
2B- Napoleon Lajoie
Lajoie used great defense and a 158 wRC+ to amass nearly 70 WAR. His best offensive season was his Triple Crown year of 1901, where he hit .426/.463/.643. Claude Ritchey, Johnny Evers, Jimmy Williams, and Danny Murphy all compiled 25-30 WAR as the second-tier second basemen.
3B- Tommy Leach
In a close battle, Leach just beats out Bill Bradley, both of whom were not great hitters, but put up nearly 40 WAR. Leach drew a few more walks, giving him the slight edge. Jimmy Collins, Art Devlin, and Harry Steinfeldt weren't too far behind, putting up 30-35 WAR, though Devlin didn't start his career until '04.
SS- Honus Wagner
By far the best player of the decade, Wagner led nearly every facet of the game, posting a 177 wRC+, +51 defense, and 489 SB to amass over 90 WAR for the decade. He was also extremely consistent, never falling below 7 WAR in a season. Bobby Wallace and George Davis had very good decades, both exceeding 40 WAR for the decade.
LF- Fred Clarke
The third straight player who spent the entire decade in Pittsburgh, Clarke nearly amassed 50 WAR with a solid all-around game, including managing the team the whole decade. Jimmy Sheckard and Topsy Hartsel each had around 35 WAR, while the quartet of Mike Donlin, Jesse Burkett, Sherry Magee, and George Stone had 25 -30 WAR in about 3500 PA.
CF- Roy Thomas
Despite not having a great average and no power, Thomas walked over 900 times in the decade, ending up with a .411 OBP and about 40 WAR. Fielder Jones ended his career with nearly 40 WAR, while Cy Seymour and Ginger Beaumont each accumulated 30 WAR.
RF- Elmer Flick
Another very close race, Flick barely beats out Sam Crawford for the right field spot. Flick used a higher walk rate and a bit better defense to amass nearly 50 WAR. Ty Cobb started his career with nearly 30 WAR in his first four seasons.
P- Cy Young, Christy Mathewson, Rube Waddell, Eddie Plank, Vic Willis, Joe McGinnity, Addie Joss
Despite starting the decade at age 33, Young leads this decade's staff, throwing over 3300 innings and not walking anyone, resulting in about 65 WAR. Mathewson began his career with nearly similar rates as Young, but with one less season, fell about 3 WAR short. The lefty Waddell was the premier strikeout pitcher, leading the league in K/9 rate seven straight seasons. Plank had a solid decade, accruing about 45 WAR. Willis and McGinnity were the compilers of the group, throwing over 3000 innings and providing about 45 WAR. Joss had a 1.87 ERA, the lowest of all the selections, though he only pitched 2200 innings and produced just over 35 WAR. There were a lot of pitchers who just missed the cut. Mordecai Brown used his three fingers to allow a miniscule 1.63 ERA in the decade, but didn't throw enough innings to make the team. Noodles Hahn had six great years before his arm gave out at age 25. Jack Chesbro also just missed with a balanced approach.
1B Frank Chance
2B Napoleon Lajoie
SS Honus Wagner
RF Elmer Flick
LF Fred Clarke
C Roger Bresnahan
CF Roy Thomas
3B Tommy Leach
P Cy Young
The #2 and #3 spots are solid, but the rest of the lineup is less than desirable.