Martinez was superb throughout the campaign for the German side as they won the treble.
“I am not mincing my words. I think that he still has a chance to give more. He has to be more involved in Bayern’s game, have more influence in his play," said Del Bosque, who could use Martinez instead of the injured Xabi Alonso in the Confederations Cup.
“The other day he played well in the final, and he is now a champion of Europe, and that is something, and he has been a permanent fixture.
“When we dropped him from the squad it was because we did not like the way he was playing, but there is no problem because he is a nice guy and you want him around, because he is a good lad.
“If we have not selected him previous, it has been purely for football reasons.”