You know the Sammy Sosa story. Early in his career, he wasn't a great player, he chased too many pitchers, didn't take walks. Then suddenly he started hitting home runs by the dozen. He and Mark McGwire had a great battle to be the one to beat out Roger Maris for the home run record. They were credited with saving the MLB after 2 strike/lockout shortened seasons.
This is his third time on the ballot, he was on 12.5% of the ballots in 2013 and 7.2% last year.
He hit .273/.344/.634 with 609 home runs, 1667 RBI, in 2354 games over 18 seasons. He was an All-Star 7 times, MVP once, and came in 2nd once, and won the Silver Slugger 6 times. He had a career 58.4 WAR.
I'll admit I was never a fan. Mark McGwire had a value before the PEDs, but Sammy didn't have much value outside of the home runs. And he's been a bit of a jerk about it all, or at least comes off as one in interviews