Santa Clara, CA (My Sportsbook) - The San Francisco 49ers made a big defensive splash on the first day of free agency, signing cornerback Nate Clements and safety Michael Lewis.

Length and financial terms of both deals weren't disclosed, but the NFL Network reports Clements was given the biggest contract ever to a defensive player -- eight years, $80 million, including $22 million guaranteed.

The 27-year-old Clements has started every game in his NFL career since joining the Buffalo Bills as a first-round draft choice in 2001. During that time he's compiled 23 interceptions. He's also run back five picks and two punts for touchdowns in his career.

Lewis had played the first five years of his pro career in Philadelphia, spending time at strong safety and even at linebacker with the Eagles in 2006. He was the team's leading tackler in 2005 and has nine interceptions for his career.

"I am excited to add two defensive starters to our team," 49ers coach Mike Nolan said. "Free agency is about adding good players with character to our team. I am confident that Nate and Michael will help make us better. Players have a choice in free agency. It is a compliment to our players and fans that Nate and Michael wanted to be with the 49ers."

The signings of Clements and Lewis should help bolster a defense that was ranked 26th against the pass last season.