The Texans tried to work out a contract extension with Robinson, but when talks stalled the team decided not to use the franchise tag. When Houston used the franchise tag on Robinson last year, the cornerback was paid $9.96 million for the 2009 season after he signed his tender.
Robinson disclosed his plans Wednesday in e-mail to KRIV-TV of Houston and the Houston Chronicle. In his e-mail, he wrote that his departure is unsurprising "when you are dealing with a tough business like the NFL." He thanked Texans management and the city of Houston for their support. In return, general manager Rick Smith expressed appreciation for his contributions.
Robinson, who is the Texans' career interceptions leader with 13, started all 16 games for Houston last season.
Robinson had played under a "franchise player" contract last season that paid him almost $10 million. Smith said the decision not to do so again for 2010 was a tough one.
Robinson was a first-round pick from South Carolina in the 2004 draft. Many regard him as the top cornerback on the market along with New England's Leigh Bodden, who also will not be tagged.
KRIV-TV first reported that Robinson wouldn't receive the franchise tag.
Information from ESPN NFL Insider Adam Schefter and The Associated Press was used in this report.