Sandstrom was waived by the Sabres on Tuesday, per PuckPedia.
Sandstrom will guard the home crease in Monday's preseason game against the Red Wings, according to Mike Harrington of The Buffalo News.
Sandstrom will guard the cage on the road versus Ottawa on Thursday, Bill Hoppe of the Olean Times Herald reports.
Sandstrom agreed to terms on a one-year, two-way contract with the Sabres on Monday.
Sandstrom was sent to AHL Lehigh Valley on Friday, Jordan Hall of NBC Sports Philadelphia reports.
Sandstrom will protect the home crease Sunday against Florida.
Sandstrom will guard the road cage Saturday against the Bruins, Kevin Kurz of The Athletic reports.
Sandstrom allowed three goals on 11 shots in "relief" as part of Saturday's 7-0 loss to the Lightning.
Sandstrom will start at home versus Ottawa on Saturday.
The Flyers recalled Sandstrom from AHL Lehigh Valley on Thursday.