Diles was injured early in practice Wednesday in what coach Gary Kubiak described as a freak accident. It occurred during a special teams, non-contact drill, according to the Houston Chronicle.
Diles was scheduled to have a rod placed in his tibia Wednesday night.
The second-year player was a 2007 seventh-round draft pick for the Texans. He has started each game this season and has 66 tackles and an interception.
"I feel terrible for Zac because he was playing so well, but through adversity comes opportunity," Kubiak said, according to the Chronicle.
Information from The Associated Press was used in this report.