2021: Brennan currently leads the Deacs in appearances on the mound with 14. He has thrown 16.1 innings collecting 11 strikeouts and posting an ERA of 4.96.

Brennan made 4 appearances on the mound for Wake in the shortened 2020 season. He totaled 3 innings pitched while allowing just one hit and striking out 4.

Brennan redshirted his freshman season at Wake Forest. He pitched for the Sanford Mainers in the New England Collegiate Summer League in 2019. In high school, he was rated as the No. 3 recruit in New Hampshire by Perfect Game. He was named Gatorade player of the year in New Hampshire and and first-team All-American by Collegiate Baseball.