He is confident Scotland Under-19 cap Fyvie will flourish after opting to move to DW Stadium despite reported interest from Fulham.
Martinez said: "He's a bright young man and will have a good environment here in which to develop, with players that have been through similar experiences and of course our fans who I know will make him feel very welcome and allow him to develop over the coming months.
"Technically he's very gifted, enjoys playing in the midfield where he can cover large areas, he's very powerful off the ball and in possession is someone who can read the tempo of the game very well.
"Also you have to remember that for such a young player he's played a lot of games in the SPL at a high standard which shows his maturity.
"Together with the rest of the squad and, of course, the other Scottish boys in the squad he'll settle in quickly I'm sure, but he's so eager to get going and take advantage of the good experience within the dressing room."