Rumours had circulated that Lawrence would turn to Campbell if he failed to capture Gray.
Lawrence brought Campbell to Blundell Park from Leicester in 2000, initially on a season long loan. His impressive form earned him a permanent £250,000 move the following summer.
The former Scotland Under 21 international is out of contract in the summer and could leave for a nominal fee now, with the club keen to rid themseleves of one of the highest contracts in the clubs history.
Lawrence has flatly denied that he is interested in Campbell though, stating the player is not what he needs, at the minute.
"We are being linked with him because I signed him at Grimsby," he said. "But we are 100 per cent definitely not interested.
"He is a good lad and he did a good job when I signed him for Grimsby, but he is not for us at this moment in time. He is not what we are looking for."