Speculation that Vice President Joe Biden will jump into the 2016 presidential election continues to grow as one of Biden's closest advisers sent his supporters a detailed email about what his presidential campaign would look like. Meanwhile, inside sources say Biden may announce a final decision about the race in as little as three days.

In a letter sent to former staffers on Thursday, Biden's close confidant and longtime friend former Delaware Sen. Ted Kaufman outlined what Biden's potential presidential campaign might entail. The letter, which was obtained by the Associated Press, also states that the vice president is "aware of the practical demands of making a final decision soon."

"If he runs, he will run because of his burning conviction that we need to fundamentally change the balance in our economy and the political structure to restore the ability of the middle class to get ahead," Kaufman told former Biden staffers in the letter.

Kaufman also said the vice president would run a heartfelt and "optimistic campaign" that is "consistent with his values, our values, and the values of the American people. And I think it's fair to say, knowing him as we all do, that it won't be a scripted affair - after all, it's Joe."

Kaufman closed the email asking Biden fans to stay in touch.

"I know in the daily ups and down of the political swirl, we all get bombarded with the tactics. So sometimes it's good to take a step back and get real again," Kaufman wrote. "Let's stay in touch. If he decides to run, we will need each and every one of you -- yesterday!"

Meanwhile, a senior official in the Democratic Party told CNN that Biden's announcement is expected in the next three days, but other Democrats say Biden may wait another week or so.

Insiders added that his family would fully support his presidential run.

Earlier this year, Biden stated that he would make a decision about the race for Commander-in-Chief by the end of the summer.