The team also released 10 players to trim its roster to 65. The Eagles have until 6 p.m. Eastern on Saturday to get their roster down to the maximum 53 players.
Wells, a sixth-round pick in 2003, has started 90 games in seven years with Arizona, including 64 in a row since late in the 2005 season.
Wells started at left guard against the Eagles in the Cardinals' 35-25 win in the 2008 NFC Championship Game and in Arizona's 27-23 loss to Pittsburgh in the Super Bowl.
The Cards moved Wells to right guard this preseason after they signed veteran left guard Alan Faneca.
"We're adding a player that has started several seasons in the National Football League and has played at a very high level during the course of his career," Eagles head coach Andy Reid said.
"He has experience at several different positions along the offensive line and he will be a welcome addition to that group. You can never have enough depth at that position as you go through an NFL season."
Just nine days before they open the regular season against the Packers at Lincoln Financial Field, the Eagles face uncertainty throughout the interior of their offensive line.
Projected center Jamaal Jackson is on target to start the opener, but he's 8½ months removed from reconstructive surgery on a torn ACL in his left knee.
Stacy Andrews, who the Eagles gave a $4.1 million signing bonus in the spring, is now splitting practice time with veteran Nick Cole, and Reid has not yet committed to Andrews as his opening-day starter.
Left guard Todd Herremans has been battling left foot soreness for over a year. He underwent surgery in August 2009, missed the first five games of last season, then sat out most of spring drills and training camp this preseason. He is expected to start the opener.
Wells is scheduled to earn $2.4 million in base salary in 2010, the final year of the five-year, $15 million restricted free agent offer sheet he signed with Buffalo in 2006. The Cardinals matched the offer and retained Wells' rights under the terms of the offer sheet.
Friday's trade is the second between the Eagles and Cardinals in the past week. The Eagles on Monday shipped rookie running back Charles Scott to Arizona in exchange for rookie cornerback Jorrick Calvin.
The Eagles released cornerback Geoff Pope, who spent six weeks on the team's active roster last year and played in one game, and veteran running back J.J. Arrington.
By releasing Arrington, the Eagles will receive a sixth-round pick from Denver in the 2012 draft, according to terms of the July trade that sent linebacker Joe Mays to the Broncos.
Also released Friday were defensive end Pannell Egboh, defensive tackle Boo Robinson, cornerback David Pender, wide receiver Dobson Collins, tight end Nate Lawrie, offensive tackle Jeraill McCuller, safety Anthony Scirrotto and running back Martell Mallett.
The Eagles also placed veteran defensive end Victor Abiamiri on the Reserve-Physically Unable to Prepare list.
Abiamiri, who underwent offseason knee surgery, is not eligible to play until the Eagles' seventh game. Starting Oct. 18, Abiamiri will be allowed to practice with the team, and the Eagles will have three weeks to either activate him, release him or place him on Injured Reserve, ending his season.