Lazaro Antonio Díaz Sr. (born March 29, 1963) is an American umpire in Major League Baseball wearing number 63, a reference to his year of birth.

Díaz was attacked by an intoxicated fan while umpiring first base in a game at Comiskey Park in April 2003.

[2] Laz stifled the attack, and the fan was later sentenced to up to 180 days in jail and one month of probation for aggravated battery.

[3] Díaz was the second base umpire when Barry Bonds broke Hank Aaron's career home run record.

Díaz is featured in Pepsi commercials with the Detroit Tigers' Johnny Damon, the Minnesota Twins' Joe Mauer and broadcaster Gary Thorne.