On Joe Mauer's player page, Baseball Reference lists two transactions:

• June 5, 2001: Drafted by the Minnesota Twins in the 1st round (1st pick) of the 2001 amateur draft. Player signed July 17, 2001.
• October 29, 2018: Granted Free Agency.

This community did not exist before Joe Mauer became a major leaguer. Mauer made his debut on 05 April 2004; SBG started posting at the Old Basement in July 2004. Granted, there were isolated pockets of Twins fans online before Mauer crouched behind the plate, but every one of the well-established communities of Twins fans came into being during Mauer's career. The Mauer Era is the era of critical mass for Twins fans online. The retirement of Joe's number is something of a milestone for all of us.

The seeds of the ongoing revolution in the evaluation of baseball players' performance stretch back to before Joe Mauer was born. By the time Mauer was swinging the bat on St. Paul's sandlots, a few forward-thinking executives had started kicking around these new approaches. By the time Joe Mauer signed with the Twins, those approaches had already jumped from theory to application in the most forward-thinking front office in the game. (That front office was not in Minnesota.)

Joe Mauer's career unfolded in a period in which enlightened baseball executives, baseball bloggers, and a few sportswriters were capable of perceiving how legendarily good Mauer was, but in which traditional executives, old school players, and (especially) sports-writing newspapermen simply lacked the curiosity, imagination, or willingness to appreciate him. The Twins' front office remained so hidebound in its approach that Mauer's own organization was simply not capable of articulating the special abilities of its franchise catcher. In Mauer's own home state, some newspapermen conspired to poison the well, turning a huge percentage of fans against the best pure hitter they might ever see play for their favorite team. Nothing in Joe Mauer's personality suggests he brought this treatment on himself. His "crime" was to be judged a good enough ballplayer to be made a multi-millionaire by the children of a billionaire banker.

Had Mauer's career unfolded exactly as it had, but a decade later, we would know with much greater certainty how amazing he was behind the plate. We know a few things. He threw out 33% of runners attempting to steal against a cumulative league average of 27% during his catching years. Baseball Info Solutions judges him about 17 runs above average in pitch calling. Johan Santana, the best pitcher to toe the rubber for the Twins since Bert Blyleven's heyday and likely the best pitcher in the American League during his own peak, threw more innings to Joe Mauer than any other catcher in his career. The only catcher with whom Johan had a lower OPS+ allowed was Ramon Castro, who caught less than a quarter of the total innings Mauer caught Johan. We can guess other things — Mauer certainly was a very good receiver, and possibly inner-circle great at framing — but we'll simply never know how he compares to the excellent catchers who came after him.

But we do know this: very, very few catchers could hit like Joe Mauer in his prime. Joe Mauer had the fifth-highest peak, judged by rWAR, of any catcher, ever. In ten seasons, from 2004–2013, Joe Mauer hit .323/.405/.468, good for an 135 OPS+. Over that span, which included a debut season derailed by a knee injury, he ripped an average of 28 doubles every year. He got an extra-base hit in 8% of his plate appearances over that stretch, but struck out just 11.2% of the time. He totaled 2051 total bases in a decade of hitting, often banged-up from his duties on the back side of the plate. Of players who caught at least 750 games and had at least 3000 plate appearances, Mauer is 3rd in Batting Runs, 7th in WAR Runs Batting, and 8th in Runs Created.

Joe Mauer was ours. He arrived just as we were gaining the ability to follow baseball with new friends we had never met, who lived far away from the territory reached by the 50,000 watts of WCCO that then still carried Herb's voice. His career was, with the exception of the disappointments his team suffered in the postseason, the career of all of our dreams when we were growing up. Nobody — especially not the cranks at the Star Tribune and their sycophants online — can take Joe Mauer's greatness away from us. We knew it, and we shared it.

Happy Joe Mauer Day, friends.