Roger Schmidt is an undeniable asset as manager but Bayer Leverkusen's dismal form and Schmidt's stubbornness are causing problems.
After joining Bayern at the age of 10 in 2000, local boy Muller, now 27, made his first-team breakthrough during Van Gaal's spell in charge.
There's great soccer being played in Europe that goes beyond the highest-profile teams. Here are three worth keeping a pulse check on.
"I want to make progress in the national team and that's only possible when I also play at the club," Wood said.
On-loan Real Madrid defender Jesus Vallejo has been "scandalously good" so far this season, according to his Eintracht Frankfurt coach Niko Kovac.
Marcelo Pletsch has been sentenced to serve nine years and two months in prison after being arrested with 793kg of marijuana, Sport Bild has reported.