The account was registered as an outside trustee plan and Putnam was not responsible for any tax reporting. As such, no taxes were withheld but a 1099-R was not issued so I can't properly complete the tax return.
You can enter a substitute Form 1099-R in TurboTax to report your pension distribution that is not reported on such a form.
To enter a substitute form 1099-R in Turbo Tax follow these instructions:
If your distribution is a normal distribution, not subject to a penalty for early withdrawal, you can enter code "7" in box 7. The distribution amount goes in box 1 and the taxable portion of it goes in box 2(a).