Smyly will start Friday night's contest against the Blue Jays, his first of the season after getting slowed by left shoulder tendinitis.
Loney has been on the DL with a mild-right oblique strain since April 8. He played for Class A Charlotte on Thursday and went 1-for-4 with a double.
Dykstra came through in his final at-bat with the team, stroking a leadoff single in the ninth inning on Thursday. Tim Beckham pinch-ran for him and scored the winning run.
Mahtook began his second stint with the team this season on Thursday after getting recalled from Durham. He did not play Thursday night.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.