No doubt a lot of behind the scenes politics at play. Rumours throughout day leading up to match had Tek as starting then suddenly Mats starts - perhaps part of the mole hunt strategy. Moreover, with a back loaded contract thru 2028 player is no doubt looking to preserve every cent that remains which precludes him from an easy sale and we know he isn’t going to play in a WC year unless Garcia gets injured - stay & don’t play, sale or loan
A loan can make sense for all parties if he is intent on playing to be fit & in form for the WC and that would start with him actually playing so potential suitors can see he is ready to play again after his recovery from injury. Had Flick, Deco et al benched him it would have unsettled player more and make a loan more complicated
Sale is unlikely due to his contract & player himself regularly choosing the nuclear option
Staying makes him a problem in the dressing room, especially if he is the leak