BERLIN: Bundesliga's tightest title race in years resumes this week following the winter break with champions Bayern Munich planning their comeback after a shaky first half to their campaign.

The Bavarians, in third place four points behind leaders RB Leipzig, take on former coach Juergen Klinsmann's Hertha Berlin on Sunday with several players still nursing injuries, including winger Serge Gnabry, Niklas Suele and Javi Martinez.

There is some good news for interim Bayern coach Hansi Flick, who took over from Nico Kovac in November, as Robert Lewandowski, the league's top scorer, returned to training this week after minor surgery late last year.

But Flick has openly demanded reinforcements during the winter transfer window if his team are to continue delivering the goods in three competitions.

Among his wishes are a winger and a defender.

"We all have high goals and we need to form the basis to reach those high goals," Flick had said during their training camp in Qatar earlier this month.

"We have to see that maybe during the winter period we can regulate a few things." So far Bayern have made no move on the transfer market.

They finished 2019 strongly, with 11 goals in their last three league games to climb back up to third but they will need to pick up where they left off with Klinsmann eager to give his former club a run for their money.

The former Germany coach took over at Hertha Berlin in November and has pledged to turn the club's fortunes around.

"I have played in cities like London and Milan where the club's importance is extremely high. Berlin deserves that as well," Klinsmann said.

Whether he will be sitting on the bench, however, is still unclear as he races to get his coaching licence up to date after having spent most of the past decade working and living in the United States.

Leaders RB Leipzig, top on 37 points, kick off 2020 at home against Union Berlin. Striker Timo Werner, who with 18 league goals is one behind Lewandowski, has one eye on the title.

"On a national level it would be nice to win the Cup (after reaching the final last year)... but if I had to chose then winning the league title is the ultimate," Werner said.

Borussia Dortmund's title hopes have been dented by an inconsistent first phase that has seen them drop seven points behind Leipzig into fourth place, and Saturday's trip to Augsburg could prove to be a tricky start to their year.

Augsburg has won three of their last four league games to climb out of trouble and into 10th place.

Second-placed Borussia Moenchengladbach, on 35 points, will provisionally go top of the table if they beat Schalke 04 on Friday.