If the entire gross amount of the distribution from the 401(k) was rolled over to the traditional IRA, the distribution and rollover will not affect your tax liability. If any amount of the distribution was withheld for taxes and you did not substitute other funds to complete the rollover of the entire distribution, the portion not rolled over is generally taxable and potentially subject to an early distribution penalty.
Since the Form 1099-R has code G in box 7, has a zero in box 2a and you in the follow-up question that the money was not rolled over to any kind of Roth account, TurboTax will not be treating it as taxable and entering this properly will not cause TurboTax to change your taxable income. Check to see that the $261K is included on Form 1040 line 4c but not on line 4d.
