managers/production companies

It is a common practice for many managers to attach themselves to projects as producers.

As with anyone I query, I would look at their track record, their reputation and what have the done for their other clients before signing.

If they do sign you on as a client, I would insist (you may not get it though) that one of the terms of your contract be that if they attach themselves as a producer to your script and the script is sold and they get paid as a producer, then they would return your managerial fee which is generally between 10% to 15%.