Neifi Neftali Perez Diaz
- Bats Both, Throws Right
- Height 6' 0", Weight 175 lb.
- Debut August 31, 1996
- Final Game July 5, 2007
- Born June 2, 1973 in Villa Mella, Distrito Nacional, D.R.
Neifi Perez was one of the most-penalized players in the first years of baseball's new steroid and performance-enhancing drug rules. He was suspended on July 6, 2007, the second time he had been caught in violation of the rules. Less than a month later, before he had finished serving that suspension, he was caught again, this time being suspended for 80 days. As a player could be only suspended once per substance use, Perez had used something improper within that period. He was the only major league player suspended by baseball for stimulant use from 2006 through August 4, 2007. The suspension effectively ended his career.
He played point guard for the Dominican Republic's Junior National Basketball team.
- NL Gold Glove Winner (2000)
- NL At Bats Leader (1999)
- NL Triples Leader (1999)
- 100 Runs Scored Seasons: 1 (1999)