Schweinsteiger contacted Babak Rafati, 46, who made an attempt on his own life while still working as a referee in November 2011.
Jonker replaces Valerien Ismael, who was fired on Sunday after a 2-1 home loss to Werder Bremen left them only two points above the relegation zone.
Cologne sporting director Jorg Schmadtke has said he is eager for the "madness" of the Chinese Super League transfer window to end.
The struggling Volkswagen-backed club said in a statement that Ismael was leaving "with immediate effect" and that a new coach would be named soon.
Robben, 33, joined Munich from Real Madrid in 2009 and last month signed a contract extension until 2018.
Hoffenheim recovered from the concession of an early goal to take a point from a 1-1 draw at Schalke.