Frank Plastina, the most senior executive for Nortel at its Triangle complex, left the company Thursday as part of a major reorganization.

Plastina had been president of the Metro and Enterprise Networks Division. He had been with Nortel for 15 years.

The division was Nortel’s largest source of revenue, producing 45 percent of the corporation’s sales.

Nortel, which hasn’t been profitable for years, is burdened by billions of debt and has seen its stock price plunge below $1, also said it was splitting the Plastina-led division into two groups, Enterprise and Wireline.

One analyst told The Canadian Press that the moves appear to be part of a move by Nortel to sell a division — perhaps the Enterprise Group.