The future form is identical to the imperfect subjunctive in some instances, so it's very easy to get them mixed up. As you said, you always need the accent at the end for the future tense: necesitará, so it's not the future in this case.
This structure is using the subjunctive because it's talking about a hypothetical situation:
If I "were to need" to go to work,....
Here is a lesson where you can see how the imperfect subjunctive is formed.
And here is a lesson on how to use this tense in this kind of hypothetical situations:
I hope it helps.
Sign in to submit your answer
Don't have an account yet? Join today
Test your Spanish to the CEFR standard