internal part needs to be reinstalled due to becoming dislodged?

There's a dream-like quality to your question coupled with a certain lack of realism to say nothing of its lack of clarity.

It may be best to enter another question with a bit more detail and include the make & model of your CD Player for instance.

Describe the shape of the plastic part and say where you think it may have come from - even if you have to guess. Tell how the player now behaves without the part in place - a big clue.

Do not expect anybody to direct you to an assembly drawing - a very very slim chance.

Good luck...

Peccavi
April 2013