New coach and players for Dortmund in Bundesliga. More concerns in defense for leader Bayern

Borussia Dortmund has new coach Niko Kovac and some new players and needs to improve fast in the Bundesliga this weekend. Bayern Munich is first with a six-point lead over Bayer Leverkusen but can’t afford the lapses in concentration that saw Vincent Kompany’s team concede three late goals last week.

- Kovac has a tough first test against Stuttgart on Saturday and a Champions League playoff game at Sporting Lisbon next week. Dortmund is 11th but a three-point gap to Stuttgart in fifth means Kovac’s team could potentially overtake their opponents on goal difference. Stuttgart ended a three-game losing run by reaching the German Cup semifinals.

- Bayern hosts Werder Bremen on Friday ahead of its Champions League playoff against Celtic next week. Bayern’s defending is under scrutiny after conceding 10 goals in the last five games. A home loss to Bremen helped derail Bayern’s title bid last year.

- Expect a culture clash when St. Pauli hosts Leipzig on Sunday. St. Pauli’s activist fan base loathes Leipzig for its corporate backing from drinks giant Red Bull.

- Kovac’s hopes of a Dortmund turnaround could depend on midfielder Carney Chukwuemeka. He arrived on loan from Chelsea on Monday looking to get his career back on track after injuries. Dortmund reached the Champions League final last season with loan players Jadon Sancho and Ian Maatsen.

- Emi Buendia had a strange debut for Leverkusen on loan from Aston Villa. He came off the bench and helped set up a goal in a 3-1 win over Hoffenheim but was then substituted off again. Saturday’s game at Wolfsburg could clarify his role.

- Michy Batshuayi is back in the Bundesliga after signing for Eintracht Frankfurt from Galatasaray to replace Omar Marmoush. The Belgian striker could play on Saturday against Borussia Mönchengladbach.

- Midfielder Leon Goretzka returns for Bayern after missing out last week with a thigh issue. Wing back Alphonso Davies remains out with a hamstring injury. Kompany said two unnamed players have colds.

- Dortmund defender Niklas Süle is back in training after an ankle injury in December.

- Frankfurt’s new forward Elye Wahi didn’t face Wolfsburg last week but could play on Saturday.

- Bayern re-signed goalkeeper Manuel Neuer and Davies, who announced his new deal with a rap, but forwards Leroy Sané and Thomas Müller are still on course to be free agents this summer and Jamal Musiala’s contract has a year to run. Young striker Mathys Tel left on loan for Tottenham on Monday.

- Dortmund signed three players on deadline day but only Chukwuemeka seems likely to be a regular starter. Rayan Cherki could have added spark to the midfield but Dortmund failed to sign him from Lyon.

"What has happened isn’t important. What’s happening and what’s going to happen are the most important things in life and soccer." - Dortmund coach Niko Kovac.

"It’s not easy to always be perfect as a person, but it’s a goal. It’s what we want to achieve." - Bayern coach Vincent Kompany responds to a question about his team’s defense.