He tweeted about his return to the 49ers on Monday, writing: "Thank you all for the support. So excited to have the opportunity to finish what I started long ago!!"
The NFC champion Niners already have a steady offensive line intact to protect quarterback Colin Kaepernick, so Snyder might be fighting for playing time in his return.
Arizona released the 31-year-old Snyder last Monday after taking two players at his position in the draft. He started 14 games for Arizona last season.
Also Monday, San Francisco hired former NFL wide receiver Ronald Curry as an offensive assistant coach. He played for the Oakland Raiders when 49ers coach Jim Harbaugh was an offensive assistant with the team.
Curry, who last played in 2008, had 193 receptions for 2,347 yards and 13 touchdowns in 76 games with the Raiders.
The 49ers also signed punter Anthony Santella to a one-year contract.
A 25-year-old Illinois product, Santella began in the NFL as an undrafted free agent with the Carolina Panthers in 2011. He went through training camp with them before his release on Aug. 27 that year.
The Niners also signed the following undrafted free agents: center Sherman Carter, fullback Alex Debniak, halfback MarQueis Gray, running back D.J. Harper, wide receiver Chuck Jacobs, tackle Luke Marquardt, long snapper Kevin McDermott, cornerback Darryl Morris, defensive lineman Lawrence Okoye, guard Patrick Omameh, nose tackle Mike Purcell and cornerback Lowell Rose.
Information from The Associated Press was used in this report.