The Leafs also announced forward William Nylander is sidelined with flu-like symptoms.
Klingberg was pulled as a precautionary measure with an unspecified injury in the first period of the Leafs’ pre-season win over the Buffalo Sabres on Wednesday in St. Thomas, Ont.
The 31-year-old from Gothenburg, Sweden, joined the Maple Leafs during free agency after signing a one-year, $4.15-million contract on July 1.
Klingberg recorded 33 points (10 goals and 23 assists) over 67 games last season split between the Anaheim Ducks and Minnesota Wild.
The Leafs play back-to-back pre-season games in Montreal against the Canadiens on Friday and Saturday.