My job offers a 401k, but I want to use a traditional IRA instead. If I opt out of the 401k, will I be able to get a deduction for contributions to the IRA?

I am basing my question on this information. https://www.irs.gov/retirement-plans/are-you-covered-by-an-employers-retirement-plan

My understanding is that, if my employer has a 401k plan, but nothing is allocated to my account, I should still be able to get a deduction for contributions to my IRA.