Prior to Saturday afternoon's game against the New York Yankees, the Red Sox announced the move, retroactive to Aug. 9. Pedroia is on the DL for a third time this season.
Manager John Farrell said there is no reason to believe Pedroia is lost for the season.
"There's nothing we have right now that suggests he won't be back to us," Farrell said on Saturday. "There's been no talk of any other kind of procedure, anything that's similar to what he went through after last season. I felt like he was getting there after the work. Obviously the irritation returned and he needs some more time at this point.
"I don't think right now that's there's a date or a number of days that says he's going to be back in the lineup. Pedey will be back when he's first available and hopefully that's as quick as possible. We have to stay focused on what his needs are and what's the best thing for him."
To fill Pedroia's spot on the 25-man roster, the RedSox recalled left-hander Robby Scott from Triple-A Pawtucket.
Pedroia, who turns 34 on Thursday, did not play in Boston's 5-4 loss to the New York Yankees on Friday night.
Farrell said Pedroia has been dealing with a recurrence of swelling and inflammation in his surgically repaired left knee and did not respond favorably to treatment.
"His knee has flared up on him," Farrell said Friday night. "He's shown that there's been a little bit of a pushback in terms of the reaction to it. Some swelling. Some inflammation."
Pedroia played only once in the past two weeks and that was an Aug. 8 game against the Tampa Bay Rays during which he drew a walk and had no hits as the designated hitter.
"All I can tell you is that it flared back up and some swelling presented itself," Farrell said. "We know he's dealing with a cartilage issue. We still got some work to do. More importantly for Pedey is get as much information to him as we can, to just allow him to get his arms around this further."
Pedroia leads the Red Sox in batting average (.303) and on-base percentage (.378), with 17 doubles, six home runs and 54 RBIs. He is one of only two qualifying American League players with more walks (41) than strikeouts (37).
In 28 games since June 26, Pedroia batted .336 (39-for-116) with a .908 OPS, hitting four home runs in his last 18 games. He leads major league second baseman in fielding percentage (.997), with his lone error of the season coming on July 19 and snapping an errorless streak of 114 games, marking a Red Sox career record at the position.
The 2007 AL Rookie of the Year, 2008 AL Most Valuable Player and two-time World Series champion (2007, 2013) is hitting .301 with a .367 on-base percentage in 1,484 career games, all with Boston.
Scott, 27, made three scoreless appearances for Pawtucket since being optioned on July 31, allowing two hits over 2 2/3 innings. He has appeared in 41 major league games this season, going 1-1 with a 3.38 ERA over 26 2/3 innings while limiting opponents to a .194 batting average.