"You might think that [Deval] Patrick’s logical path is to compete with Biden for black voters, and with Warren and Sanders for New Hampshire voters..."

"... And sure, it would help Patrick if he can peel off some of Warren’s well-educated liberal voters, particularly in New Hampshire. And to win the nomination, he will probably have to close the big lead that Biden has with African-Americans. But I think the real opening for Patrick is essentially to replace Pete Buttigieg as the candidate for voters who want a charismatic, optimistic, left-but-not-that-left candidate. Patrick, I think, is betting that there’s a 'Goldilocks' opportunity for him — 'Buttigieg but older,' or 'Biden but younger' — a candidate who is viewed as both safe on policy and safe on electability grounds by Democratic establishment types and voters who just want a somewhat generic Democratic candidate that they are confident will win the general election.... On paper, Patrick seems fairly similar to Cory Booker and Kamala Harris — charismatic, black, left-but-not-that-left. But... Patrick has a last-mover advantage — he’s seen how the other candidates have ran and can begin his candidacy to take advantage of perceived weaknesses.... [M]ore importantly, Booker and Harris both spent the first half of the year trying to win some of the more liberal voters, who are likely now with Warren and Sanders. That may have made Harris, in particular, appear as though she was trying to be all things to all people. Patrick can now enter the race knowing that he is trying to win Democrats who self-identify as 'moderate' and 'somewhat liberal,' basically conceding the most liberal voters to Warren and Sanders."

From "Why Deval Patrick Is Making A Late Bid For The Democratic Nomination" by Perry Bacon Jr. (at FiveThirtyEight).

It's not that late. I think it's smart to hold back, observe, and then enter when you see the negative space created by all the other candidates. Step right into it.