The Texans released Allen from the reserve/physically unable to perform list with an injury settlement, the team announced Friday.
Allen missed the final two games of the 2017 season with a concussion. Still recovering from multiple ankle injuries, he was placed on the PUP list in May.
A second-round draft pick by the Chiefs in 2012, Allen started 26 games at guard and tackle over two seasons in Houston after signing a four-year deal back in 2016. His release leaves coach Bill O'Brien with even more questions about a shaky offensive-line group that looms as the chief concern entering training camp.
Although the Texans added Zach Fulton, Senio Kelemete and Seantrel Henderson in free agency, all three have been just part-time starters for their former clubs. O'Brien will have to count on developing tackle Julie'n Davenport and rookie Martinas Rankin -- currently recovering from offseason foot surgery -- to emerge as reliable bodyguards for second-year quarterback DeShaun Watson.