Brummett spent 2007 and 2008 in the lower levels of the Phillies' farm system before being promoted to the Double-A Reading Phillies in 2008. He split his time in the years between 2009 and 2012 between the Single-A Clearwater Threshers, Reading, and the Triple-ALehigh Valley IronPigs, posting a 14–30 win–loss record over 121 games, including 30 starts.
Philadelphia Phillies
Brummett's contract was purchased by the Philadelphia Phillies on September 30, 2012, four games prior to the season's conclusion. One month after last pitching in a game, Brummett had returned home to Utah to ready himself for winter baseball. Brummett made his major league debut as the Phillies' last pitcher of the last game of the season. It was October 3, a 5-1 loss at Washington. Brummett entered the game in the bottom of the eighth inning in relief of Jonathan Papelbon with one out and the bases empty. After giving up consecutive singles to the first two batters he faced, he struck out Jesús Flores and pinch hitterChad Tracy to end the inning.
The Toronto Blue Jays claimed Brummett off waivers from the Phillies on October 18, 2012. He was designated for assignment on October 23 to make room for David Herndon on their 40-man roster. According to the Jays transaction page, Brummett was assigned outright to their Triple-A affiliate Buffalo Bisons on October 26. On February 17, The Blue Jays invited Brummett to Spring Training as a non roster invitee. Brummett started the 2013 season with the Double-A New Hampshire Fisher Cats, and was called up to the Triple-A Buffalo Bisons on April 7. Four days later, Brummett was sent back to the Fisher Cats.
Los Angeles Dodgers
Brummet signed a minor league deal with the Los Angeles Dodgers in February 2014 and was assigned to the AA Chattanooga Lookouts, where he was selected to the mid-season Southern League all-star team. He finished the season with a 4–5 record and 2.79 ERA in 13 starts for the Lookouts. He was released on August 11, 2014.
Brummett spent the 2011 and 2012 offseasons playing for the Tiburones de La Guaira of the Venezuelan Winter League. In 2011, Brummett went 1–0 with a 1.59 ERA in 3 starts during the regular season. He helped lead the Tiburones to the League Championship series where they would eventually win the Championship. In 2012, Brummett went 4–1 with a 3.79 ERA in 11 games started. In 57 innings pitched, he had 27 strikeouts while allowing 19 walks.
Post-playing career and death
After retiring from baseball, Brummett became a pilot and certified flight instructor. During the COVID-19 pandemic, he participated in Goggles for Docs, a nonprofit grassroots drive that amassed ski or snowboard goggles to give to health care workers. Brummett was killed in an airplane crash in the mountains north of Alpine, Utah, on July 3, 2020, at the age of 35. According to the local sheriff's office, Brummett and three passengers died in the crash.