On October 4, 2001, Wolf served as third base umpire when Rickey Henderson broke Ty Cobb's runs scored record.[3]
Wolf drew criticism from ESPN announcers after he ejected Chicago Cubs starting pitcher Ted Lilly at the start of a game on June 10, 2007, against the Atlanta Braves. Wolf ruled that Lilly had intentionally thrown at the batter's head, and immediately ejected the pitcher. While such a penalty is uncommon without a formal warning to both teams, such action is permitted by baseball's rules.[4]
Wolf missed several months during the 2013 season due to an apparent back injury. He worked a rehab assignment at Triple-ACharlotte the weekend of July 18–19 en route to a return to the Major Leagues.[5]
On August 2, 2015, Wolf was involved in a series of controversial events in a game between the Toronto Blue Jays and the Kansas City Royals. The controversy was based upon a warning by Wolf to both teams after Blue Jays batter Josh Donaldson was struck by a pitch in the first inning by Edinson Vólquez. The benches were cleared after a number of pitches could have resulted in the Royals' pitcher's ejection, and did not, but a pitch by the Blue Jays' relief pitcher Aaron Sanchez that hit Alcides Escobar immediately resulted in Sanchez being ejected.
Wolf is married and resides in Ahwatukee, Arizona. His younger brother Randy was a pitcher in the major leagues from 1999 until 2015. To avoid a conflict of interest, he would be removed from assignments if his crew was assigned to work any game where Randy was on either team's roster.