On July 31, 2003, the Yankees traded for Aaron Boone. He hit .254 with six home runs in the remaining two months of the regular season and, except for one well-timed home run, played quite poorly in the postseason. That well-timed home run came in his only at-bat of Game 7 of the ALCS, a game which he did not start. He hit it off Tim Wakefield in the bottom of the eleventh inning and it sent the Yankees to the World Series.
Albert Pujols is probably the best pure hitter and one of the four best all-around players I’ve ever seen (I’ll get to the other three in a minute). He was either the best or second best player in the game for more than a decade and he led the Cardinals to three pennants and two World Series wins. He’s seventh all time with 614 home runs, he ranks ninth all time with 1,918 RBI, and his 99.4 career WAR is the twelfth-highest among position players since WWII.