Speaking two days before Juventus begin the defence of their Serie A title at home to Cagliari, Marotta.
Speaking two days before Juventus begin the defence of their Serie A title at home to Cagliari, Marotta said the Turin giants would not be making "extravagant" purchases before the transfer period ends on August 31.
But he claimed there is a growing belief that the end of the summer transfer period must be brought into line with the start of the season to stop agents unsettling players.
"It is a wretched (summer transfer) market, and all clubs are in favour of seeing the window closed earlier," Marotta told Jtv, the club's official channel.
"Once the league season starts this is a point we have to discuss further. Even moreso because the summer transfer market is now full of agents trying to get a move for their players; some of whom, at the first exclusion (from the squad), perhaps in a friendly, express the desire to switch clubs.
"It risks making it an open air market that has nothing to do with the values of sport."
Juventus secured a record sixth consecutive league title in 2017 to wrap up a record third successive league and Cup double, but are expected to be pushed hard by AC Milan and Inter Milan this coming season.
Having sold long-time defender Leonardo Bonucci to Milan for 41.5m euros, Marotta said coach Massimiliano Allegri had now just about filled his roster.
"There's still two weeks left (until the transfer deadline), we'll see what happens but certainly nothing extravagant," added Marotta.
"We know we have a competitive squad full of top professionals. For us, it's difficult to improve on that."