Jackson signed a one-year contract Tuesday, Chris Jenkins of the Bills' official site reports.
Potential starter Mike Edwards has a hamstring injury that's more than a day-to-day thing, so the Bills are bringing in reinforcements. At 36 years old, Jackson is on the downside of his career, but he has a strong history as a key starter for both the Texans and Broncos for a number of years and can help the Bills if they run into depth issues.