The moves came after Texas rookie sensation Deshaun Watson went down with a torn ACL in Thursday's practice. Watson is out for the season.
Tom Savage is currently listed as the team's starter.
That leaves Kaepernick still unemployed. Kaepernick opted out of the final year of his contract with the San Francisco 49ers in March. He was due $16.9 million.
McGloin, 27, has completed 58.1 percent of his passes for 1,868 yards, 11 touchdowns and 11 interceptions in 13 career contests. He owns a 1-6 record as a starter. McGloin has ties to the Texans' head coach, as Bill O'Brien coached him in 2012 at Penn State. That season, McGloin completed 60.5 percent of his passes for 3,271 yards, 24 touchdowns and five interceptions. McGloin played for the Oakland Raiders from 2013 through last season.
Yates, 30, was a fifth-round pick by the Texans in the 2011 NFL Draft. He was signed by the Atlanta Falcons in 2014 before returning to the Texans in 2015. He played for the Miami Dolphins in 2016. For his career, Yates has completed 58.1 percent of his throws for 1,534 yards, six scores and eight interceptions in 18 games. He owns a 4-3 record as a starter. Yates and Watson worked together during the offseason, according to CBS.
Kaepernick owns a 28-30 record as a starter. He has completed 59.8 percent of his throws for 12,271 yards, 72 scores and 30 interceptions. He also has 2,300 rushing yards and 13 scores during his six-year NFL tenure. The second-round pick in the 2011 NFL Draft also has playoff experience. Kaepernick owns a 4-2 mark in the postseason, while completing 58 percent of his passes for 1,374 yards, seven scores and five interceptions.
He turned 30 years old on Friday.
The Texans host the Indianapolis Colts at 1 p.m. Sunday at NRG Stadium. Indianapolis has allowed the second-most passing yards in the NFL.