This Form 1099-R does not sound like it is for a distribution of an excess contribution. It's reporting a regular distribution of an amount that you contributed to the 401(k) after-tax. Such amounts often appear in your 401(k) as a result of repaying a defaulted 401(k) loan after a deemed distribution. It's also possible that you made a deferral of more than the limit that was permitted to be excluded from your income and under the terms of the plan was instead allowed as an after-tax contribution, not an excess contribution.
If this was truly a distribution of after-tax basis that was in your 401(k) as indicated by the Form 1099-R, not an excess contribution, yes, it can be rolled over tax free to a Roth IRA within 60 days of the date it was distributed. If not rolled over within 60 days, unless you would qualify for a waiver of the 60-day deadline, it must remain distributed. Rolled to a Roth IRA or not, it's not taxable.
