Teamer played four seasons for the Tulane Green Wave. He became a starter at cornerback towards the end of his freshman season.[2] He made 48 tackles (3.5 for loss) with two passes broken up, a blocked kick and a fumble recovery, which he returned 52 yards for a touchdown in his junior season.[3] As a senior, Teamer finished second on the team with 72 tackles along with six passes broken up and an interception and was named second team All-American Athletic Conference.[4] He finished his collegiate career with 197 tackles, 15 passes defensed, three interceptions and three sacks in 46 games played.[5]
Teamer signed with the Los Angeles Chargers as an undrafted free agent on April 27, 2019.[7] He made his NFL debut on September 22, 2019 against the Houston Texans, starting at strong safety and making seven tackles.[8] Teamer recorded his first career interception on October 20, 2019 in a 20-23 loss to the Tennessee Titans, picking off a pass thrown by Ryan Tannehill.[9]
In Week 8 against the Chicago Bears, Teamer recorded a team high 8 tackles and sacked quarterback Mitch Trubisky once in the 17–16 win.[10] Teamer finished his rookie season with 40 tackles, one sack, two passes defended and one interception in seven games played (six starts).[11]
On July 13, 2020, Teamer was suspended for the first four games of the 2020 NFL season for violating the NFL's policy on substance abuse.[12] He was waived on August 1, 2020.[13]
Indianapolis Colts
On January 10, 2021, Teamer signed a reserve/futures contract with the Indianapolis Colts.[14] He was waived on May 14, 2021.[15]
Las Vegas Raiders
Teamer signed with the Las Vegas Raiders on June 3, 2021.[16] He was placed on injured reserve on October 20.[17] Teamer was activated on November 20.[18]
In Week 12 against the Dallas Cowboys, Teamer was ejected by the game for a fight on the sideline with Kelvin Joseph.[19] Teamer finished his season playing in 10 games (two starts), recording 18 tackles.[20]
In 2022, Teamer appeared in all 17 games for the first time in his career, with three starts, and recording 35 tackles (23 solo).[20]
On March 15, 2023, Teamer re-signed with the Raiders.[21] He was placed on injured reserve on October 18.[22] He was activated on November 25.
On November 25, 2023, Teamer was arrested for driving under the influence (DUI) and speeding. He was waived by the Raiders on November 27.[23]
New Orleans Saints
On June 20, 2024, Teamer signed with the New Orleans Saints.[24] He was released on August 27.[25] Teamer was re-signed to the practice squad on October 22.[26]