The deal is worth $43.5 million and includes nearly $21 million in guaranteed money, per a league source.
It includes a $12.5 million signing bonus and a $30 million payout over the first three years.
"This was a really tough time for Arian, because he took a major risk," McCartney said. "He really took to heart that the Texans basically said, 'Hey, we know you had a great year (in 2010), but we need to see it again.'"
The deal includes significant guarantees for Foster in terms of skill, injury and salary cap.
In terms of the guaranteed money at signing, including bonus and salary guaranteed for skill, injury and cap, here's how some recent running back deals stack up: DeAngelo Williams ($21 million), Foster ($20.75 million), Adrian Peterson ($20.25 million) and Chris Johnson ($13 million).
A former undrafted free agent from Tennessee, Foster was a restricted free agent.
The contract is similar to the Williams deal signed last year as an unrestricted free agent.
Williams signed a $43 million deal that included $21 million guaranteed through a $16 million bonus.
Foster, 25, rushed for 1,224 yards and 10 touchdowns last season despite dealing with a hamstring injury.
An NFL rushing champion in 2010, Foster is prized for his versatility.
He caught 53 passes for 617 yards and two touchdowns last season.
The Texans made it to the playoffs for the first time in franchise history with Foster operating as their offensive centerpiece.
With quarterbacks Matt Schaub and Matt Leinart injured and rookie quarterback T.J. Yates in the lineup, Foster led the Texans to a wild-card playoff win over the Cincinnati Bengals.
Their season ended in the AFC divisional round, losing to the Baltimore Ravens. The Associated Press contributed to this report.
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