Allen is battling Jeff Driskel for the No. 2 quarterback spot. Both are on one-year deals with the Texans. Allen signed a $2.5 million deal after playing for the Washington Commanders for the previous two seasons.
Allen completed 67.9% of his passes for 730 yards and five touchdowns in the six games he played for the Commanders. His best season was in 2019 with the Carolina Panthers, when he threw for 3,322 yards and 17 touchdowns and logged a 5-7 record as a starter.
Starting quarterback Davis Mills is expected to play a couple of series in the preseason opener, according to Texans coach Lovie Smith, and Driskel will take the rest of the snaps.
Pro Football Network was first to report that Allen tested positive.