The 28-year-old Brazilian-born Italian passport holder is expected to man the left flank for the team which would be led by Syed Rahim Nabi.
Moritz played in the second tier English Championship for Bolton Wanderers last season and also has the experience of featuring in the Turkish and Brazilian leagues. For Bolton, Moritz made 27 appearances, scored seven goals and provided three assists.
Commenting on the decision to make Nabi as the skipper, team coach Peter Reid said the player had natural leadership skills.
"From the couple of weeks I have worked with the team, I have found him a natural leader, good communicator and a bubbly character within the dressing room. I think Nabi has great experience and knowledge of the game. Manuel Friedrich would be the vice-captain," Reid said.
About the ISL game against the Kolkata franchise, he said, "This is the start of the competition and so it is a massive game. It is a big opportunity to play here and hopefully we will come up with the right result."