Joe Royle told the club site: "The lad has done okay and he has got talent but we will not be taking it further.
"The big question is whether he is better at 18 than the central defenders we have and we've just handed Chris Casement a two year deal and we don't want to halt his progress."
Krol came to Portman Road afer a trail at Premiership outfit Machester City.
Meanwhile, Royle has stated that a central defender is his main transfer target, ahead of next season. He has announced that a pool of scouts are currently targeting defenders and he may also look to secure the services of on-loan defender, Jay McEveley on a permanent basis.
McEveley has been on the sidelines since the game at Ninian Park but is pencilled in for a return to the Reserves next week. Jay is hopeful he may return to make one or two first team appearances before the end of the current campaign.