Mueller and Gnabry back in Bayern Munich training

Mueller, 31, had been in isolation since testing positive just before Bayern won the Club World Cup final in Qatar a fortnight ago. After being examined by their head of fitness, doctor Holger Broich, Mueller trained individually on Thursday at Bayern's training complex, the club said.

Meanwhile Gnabry, 25, trained with the team for the first time since tearing a thigh muscle in the Club World Cup final win over Mexico's Tigres. No date has been given for when Mueller or Gnabry will play again.

Bayern host Cologne on Saturday holding a two-point lead at the top of the Bundesliga. Holders Bayern are on the verge of the Champions League quarter-finals after their 4-1 thrashing of Lazio in Tuesday's last 16, first leg in Rome.

However, Bayern struggled in the Bundesliga last week after a shock defeat in Frankfurt and home draw with strugglers Bielefeld slashed their lead in the table to two points.