Bayern Munich newcomers Sadio Mané and Matthijs de Ligt were training on Monday even though the team officially had the day off.
Bayern Munich returned from a week-long trip to the U.S. and coach Julian Nagelsmann had given the players Monday off to recover before starting final preparations for the upcoming season.
But Mane and de Ligt trained together with Bayern Munich’s head of fitness, the club said in a statement on Monday.
Former Liverpool forward Mane left the team to be present for Thursday’s African Player of the Year award in Morocco which he won, and then returned to Munich.
Centre-back de Ligt joined Bayern Munich on Tuesday in the U.S., immediately after signing from Italy’s Juventus.
Bundesliga champions Bayern Munich start the season on Saturday in the German Super Cup at Cup winners RB Leipzig.
Their first Bundesliga game is six days later at Europa League winners Eintracht Frankfurt.