After hitting 112 homers from 1995 to '97, including 36 in the last of those years, Sosa hit a modest nine through the first 49 games of '98. Challenged by Cubs hitting coach Jeff Pentland to draw 100 walks, Sosa had 26 bases on balls to that point and a .333 average. In June, though, Selective Sammy became Slammin' Sammy, as he produced a record-setitng 20-homer month that included a three-homer game on June 15 and a trio of two-homer games. The showing catapulted him into the race for Maris' record; through the end of June, he was tied with Ken Griffey Jr. at 33, trailing Mark McGwire by four.
He overtook Griffey and trailed McGwire by three at the end of July, 45-42. McGwire beat Sosa to 50 homers by three days (Aug. 20 for the former, Aug. 23 for the latter), and while both finished the month with 55 through 138 team games, Sosa could only watch and congratulate when McGwire matched and then surpassed Maris against his Cubs in a two-game series on Sept. 7 and 8. Sosa hit four in three games from Sept. 11 to 13 to bring the pair into a tie at 62, but he hit just four the rest of the way. Even so, he helped the Cubs to an NL wild card berth after winning a Game 163 play-in, then won NL MVP honors, though his feel-good season was later cast in a different light due to his connection to alleged PED use.