METAIRIE, La. -- The New Orleans Saints continued their extreme makeover with another flurry of moves Friday.
The Saints signed former Buffalo Bills running back C.J. Spiller, traded receiver Kenny Stills to the Miami Dolphins for linebacker Dannell Ellerbe and a third-round draft pick, and released backup cornerback Corey White.
Spiller's deal is $18 million over four years with $9 million guaranteed and a $5 million signing bonus, a source told ESPN NFL Insider Adam Schefter.
The Stills trade was the biggest surprise among Friday's moves because he is a young, cheap player on the rise. Now New Orleans has traded away two of its top receiving targets after trading tight end Jimmy Graham to the Seattle Seahawks earlier in the week.
However, Stills was another wanted commodity the Saints felt they could use to help in other areas. General manager Mickey Loomis explained after the stunning Graham trade that the Saints felt like bold moves were necessary after last year's disappointing 7-9 campaign and that they especially wanted to add resources they could use to help fix their defense.
The Saints have now added four players this offseason (Spiller, Ellerbe, cornerback Brandon Browner and center Max Unger) while trading away Graham, Stills and guard Ben Grubbs and releasing linebacker Curtis Lofton, running back Pierre Thomas and White.
New Orleans now has two first-round picks and two third-rounders in this year's draft.
Stills, 22, caught 63 passes for 931 yards and three touchdowns last year, coming on especially strong late in the season after receiver Brandin Cooks went down with a thumb injury.
The 6-foot, 194-pounder was a fifth-round draft pick out of Oklahoma in 2013 who earned a part-time starting job right away as a rookie, finishing that year with 32 catches for 641 yards (a NFL-best 20.0 yards per catch) and five touchdowns.
"We are excited that we were able to acquire Kenny Stills," Dolphins general manager Dennis Hickey said Friday. "He is a talented, young and ascending player who has been very productive in his first two seasons in the league."
The Dolphins needed help at receiver. No. 1 receiver Mike Wallace, who is due $9.9 million this season, was traded to the Vikings. They released two veterans in former starter Brian Hartline and backup Brandon Gibson.
Ellerbe, 29, was expendable for the Dolphins. He missed 15 games last year with a season-ending hip injury, and backup linebacker Jelani Jenkins took his place and led the Dolphins with 110 tackles. Ellerbe was scheduled to make $8.45 million in 2015 and had a total of $21 million remaining over the next three years. But he will reportedly restructure his deal before joining the Saints -- who started this offseason more than $23 million over the salary cap.
The 6-1, 245-pound Ellerbe should replace Lofton as an inside linebacker for the Saints. He began his career with the Baltimore Ravens and has 285 tackles and 6.5 sacks in six seasons. New Saints front-office member Jeff Ireland was the Dolphins' GM when Miami signed Ellerbe to his big contract in 2013.
The Saints deemed Graham and Stills expendable in part because they believe they can continue to produce a strong offense, as they always have in the Drew Brees-Sean Payton era. However, they have continued to invest heavily in their backfield, re-signing top running back Mark Ingram to a four-year, $16 million deal before adding Spiller.
New Orleans apparently wanted to continue its tradition of having a dynamic runner/receiver threat in the offense. Spiller is cut from the same mold as former Saints runner/receivers Reggie Bush, Darren Sproles and Thomas.
"I've been following this offense very closely," Spiller said. "The way that they use their running backs in general is very intriguing. If you were in my position, you would be a fool not to visit or at least see how they could utilize your skill set, especially my type of skill set."
The Saints traded away Sproles last year, cut Thomas last week and did not tender an offer to runner/receiver Travaris Cadet, who was a restricted free agent. They still have power runner Khiry Robinson in the fold.
Spiller, 27, was a free agent for the first time since being selected ninth overall by the Bills in 2010.
Considered one of the fastest and most athletic running backs in the NFL, Spiller is coming off a pair of disappointing, injury-hampered seasons in which he saw diminished production as both a runner and receiver.
Last season, Spiller missed seven games with a broken collarbone and finished the season averaging 3.8 yards per rush, tying his career low set in 2010. He also set career lows in receptions (19) and receiving yards (125).
"Having the injury, that kind of hurt but made me a better person," Spiller said. "It put some things in perspective for me. It made me more mentally tough than I thought I was, but now I am back 100 percent and feel great. ... My best years are yet to come."
Spiller's best season came in 2012, when he gained 1,703 total yards (1,244 rushing, 459 receiving) and scored a career-high eight touchdowns.
He told the New York Daily News in January that he "had [his] best years in the league" under New York Jets offensive coordinator Chan Gailey, who served as Bills head coach from 2010 to 2012.
Gailey's spread-style offense allowed the elusive Spiller to excel in the open field. When Doug Marrone took over as Bills coach in 2013 and implemented more of a power-running scheme, Spiller was used on more between-the-tackles runs, and his production declined.
ESPN.com Bills reporter Mike Rodak, ESPN.com Dolphins reporter James Walker and The Associated Press contributed to this report.