He has played consistently as a central defender this season together with Hummels as Boateng had a season in which he was injured a lot.
He did not play many matches during Pep's time in Germany - had a fully knee damage (not just an ACL) in the Supercup match against Dortmund a month after Pep arrived in Munich - was a year fully out and then had two years in which he often was injured - still knee problems or muscle problems.
There is no need to have further discussions about it. Bayern has 4 central defenders, Martinez, Boateng, Hummels and Süle - and in the recent seasons atleast one of them was out for months. Süle still is a talent that has to grow to get Bayern quality. All of them will get enough playing time - maybe Süle will not if all stay healthy.
He has contract until 2021. It is hard to get very good and proven defenders on the market and they do not go cheap. Bayern does not sell players they need and want to hold if it is not somebody that was not used much and wants to go because of playing time or a contract that will run out in the next season. That is not the case here.
And - Martinez is one of the foreign players I really see retiring at Bayern somewhen - if he does not return to Bilbao or Pamplona and plays the last 2 years of his career at home. He is more connected to the club than a lot of german players were in the recent years or decades. He does not have any reason to leave the club - he had a starting spot in last seasons first team because Boateng was injured for so long and it will be an even fight for the three defenders in which Ancelotti will rotate as he can do it as it does not make much difference in the quality of the three.
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Does not look like Munich as it is probably Ibiza where he was some days ago. He has his summer camp for kids in the next days in his home region. Training in Munich starts July 1st - but he still is handicapped with a shoulder injury he got climbing mountains in the recent weeks of last season. The only Bayern player that is in or around Munich right now is Müller - and he did not leave for more than a week. The others are touring the world and have rarely been seen in Munich since end of the season.