The two-time NFL Defensive Player of the Year didn't immediately sign the deal that was reviewed by the NFL Management Council and the NFL Players Association.
The contract is an incentive-laden deal, according to NFL Players Association records. Lewis will be paid $10 million in the first year.
The deal could be worth up to $44.5 million, with $12.25 million in bonuses, the Baltimore Sun reported, citing the NFLPA.
According to the newspaper, Lewis will receive a $6.25 million signing bonus this year, a $2.75 million roster bonus and $1 million in base salary. In 2010, the Ravens would have to pay a $1.25 million roster bonus and pay Lewis $4.25 million in base salary. In 2011, Lewis would get a $2 million roster bonus and $4.5 million in base salary.
The Sun broke down the final four years of the deal as: $4.95 million in 2012, $5.4 million in 2013, $5.85 million in 2014 and $6.3 million in 2015.
The 33-year-old Lewis is now under contract through the 2015 season. But the deal includes option years in the second and third years.
The 10-time Pro Bowler's previous seven-year, $50 million contract expired after last season.
Information from The Associated Press was used in this report.