To further the Mattingly/Mauer thing:
I'm not even sure how they're arguing that the two guys are the same beyond "were really good, didn't play as long as they should've."
Accolades:
Mauer: MVP, 6x All-Star, 3x Gold Glove (all as C), 5x Silver Slugger, 3x Batting Title, 0 World Series
Mattingly: MVP, 6x All-Star, 9x Gold Glove (all as 1B), 5x Silver Slugger, 1x Batting Title, 0 World Series
Career stats:
Mauer: 7960 PA, .306 avg/.380 obp/.827 ops, 143 HRs, 923 RBIs, 11.8% BB, 13% K, 123 wRC+, 53 fWAR
Mattingly: 7721 PA, .307 avg/.358 obp/.830 ops, 222 HRs, 1099 RBIs, 7.6% BB, 5.8% K, 124 wRC+, 40.7 fWAR
I love Don Mattingly. Even when he doesn't fix his sideburns. But if we're arguing that Joe Mauer is somewhat of a borderline HOF because of his kneecapped longevity then Mattingly is a borderline not-HOFer given that
a) Their accolades for their respective careers are relatively close with his advantage being the comparatively dumb gold gloves (at the least valuable defensive position compared to Mauer's at one of the most difficult/valuable) and his disadvantage being the fewer batting titles (which, again, Mauer won while playing a high value defensive position not known for its offensive output.
b) their slash lines are somewhat similar with Mauer having a notable OBP advantage while Mattingly having a similar SLG advantage (which I didn't list because I did show OPS)
c) Mattingly's big advantage statistically is in his power #s, which would've in no small part been helped by Yankee Stadium playing to lefty hittiers while Mauer spent most of his career in the cavern of Target Field
d) Mauer has significant WAR advantage in no small part to being an elite defender at a premium position.
Again, no disrespect to Mattingly. He was a great hitter and an excellent player. But he's not quite on Mauer's level and that means he's also not quite a hall-of-famer.