it is said that the project manager is a vital part of the project procurement process. However, the bid duration stretches over weeks, months, and...

it is said that the project manager is a vital part of the project procurement process. However, the bid duration stretches over weeks, months, and even years. During that time, the project manager is not "managing" the project on a day-to-day basis. What else is the project manager doing? If he/she is assigned to manage another task, how can they devote enough time and energy to the bid process for this new contract?