Keizer was born to a family of Latvian descent,[1] and grew up in Portage, Michigan.
He attended Portage Northern High School where he played baseball and football.
[2] Keizer was a member of the Grand Valley State Lakers, redshirting as a true freshman.
He was cut at the end of training camp but was re-signed to the team's practice squad.
[6] He was waived during final roster cuts, but was re-signed to the practice squad and remained there for the rest of the season.