[2][3] After his junior year in college, Gossett was selected by the Oakland Athletics in the second round of the 2014 MLB draft.

He started 2016 with the High–A Stockton Ports and was promoted to the Double-A Midland RockHounds and Triple-A Nashville Sounds during the season.

[6] Gossett began the 2017 season with Nashville, and was promoted to Oakland on June 14 to make his major league debut that day against the Miami Marlins.

[10] In 20 appearances (18 starts) with the Triple-A Worcester Red Sox, he pitched to a 4.22 ERA and 7–5 record while striking out 81 batters in 98 innings.

In 27 games (16 starts) split between Double-A Wichita and the Triple-A St. Paul Saints, Gossett accumulated a 5-3 record and 4.32 ERA with 94 strikeouts across 100 innings pitched.