After a second-successive 1-1 draw on Tuesday, Bayern Munich sporting director Hasan Salihamidzic it was "high time we flicked the switch", warning "the title is at stake".Frankfurt however missed a golden chance to close the gap with Bayern to three points on Wednesday, drawing 1-1 at Freiburg.
"Jay is a seasoned, tough-tackling and aerially strong defender who really needs no further introduction," said Hoffenheim sporting director Alexander Rosen
Another day, another game-winning goal for Gio Reyna.
The 50-year-old Armas worked under interim coach Ralf Rangnick at Manchester United last season, leaving before Erik ten Hag took over as manager.