McAmmond left the game with a concussion after he was sent to the ice by a flying body check from Philadelphia prospect Steve Downie.
The 13-year veteran did not move his hands or his feet while he was fully strapped onto the stretcher and taken off the ice. A team spokesman confirmed he had suffered a concussion, and subsequently moved his extremities, and was taken to a hospital for further evaluation.
McAmmond, who missed the final two games of last spring's Stanley Cup final against Anaheim after he suffered a concussion when he was elbowed in the head by Ducks defenseman Chris Pronger and knocked out of Game 3.
Ray Emery stopped seven of nine shots in his first appearance since Game 5 of the Stanley Cup final last spring. Emery, who started each of Ottawa's 20 playoff games, played the first two periods in his return from offseason surgery on his left wrist.
Daniel Alfredsson tied it at 1 when he scored a short-handed goal on a breakaway 11:42 in after he stripped the puck off Scottie Upshall. Shean Donovan scored Ottawa's fourth goal 3:22 into the third.
The Senators have won each of their five preseason games, outscoring their opponents by a margin of 19-10 overall.
Martin Gerber, who started each of Ottawa's four previous preseason games, made 10 saves in the third.