Effler made his MLB debut with the Phillies in 2021. He played college baseball at the University of Louisville.
Effler was born on February 19, 1993, in Owensboro, Kentucky. He attended Owensboro High School, where he played baseball and football.
Effler played college baseball at the University of Louisville from 2012 to 2015. In 2014, he was named the American Athletic Conference (AAC) Pitcher of the Year. He was also named a First Team All-American by the National Collegiate Baseball Writers Association (NCBWA) and the American Baseball Coaches Association (ABCA).
In 2015, Effler was selected by the Philadelphia Phillies in the 15th round of the MLB draft.
After signing with the Phillies, Effler was assigned to the Williamsport Crosscutters of the Class A-Short Season New York-Penn League. He was later promoted to the Clearwater Threshers of the Class A-Advanced Florida State League, and the Reading Fightin Phils of the Class AA Eastern League.
In 2018, Effler made his Triple-A debut with the Lehigh Valley IronPigs. He was selected to the International League All-Star Game that year.
Effler was called up to the Phillies in September 2020. He made his MLB debut on September 17, against the Washington Nationals. He pitched 6⅔ innings, allowing two runs and striking out six batters.
In 2021, Effler made the Phillies' Opening Day roster. He pitched in relief in 20 games during the season, posting a 3-0 record with a 3.74 ERA.
In 2022, Effler again made the Phillies' Opening Day roster and was used primarily as a starter. He made 13 starts for the team and pitched in relief 20 times, finishing with a 5-5 record and a 4.04 ERA.