It’s time to cross your fingers and hope for the best.

The Celtics have 17 games remaining and are tied for the best record in the East.

But for a team that’s been to the NBA finals two of the past three seasons, tied atop the conference, the Celtics are very much a team in transition.

Back in the day, Danny Ainge was part of a Celtics team that couldn’t evolve from a championship contender in the 1980s to a playoff power in the ’90s.

As the original Big Three of Larry Bird, Robert Parrish, and Kevin McHale got older, the lengths of the team’s playoff runs grew shorter.

Now, as general manager, Ainge is trying to keep that from happening again.

That’s why he shocked the basketball world last month with the trade that sent Kendrick Perkins to Oklahoma City. He brought in 24-year-old Jeff Green with an eye to the future, a scorer who can help this team move on as the current Big Three ages.

We all thought Green could play.

What we didn’t expect was that the other player, Nenad Krstic, would fit in so nicely. Krstic has become the basketball equivalent of Mike Lowell, the throw-in to the Josh Beckett deal who became the 2007 World Series MVP.

We’re not saying Krstic will get any sort of MVP award in June, but he’s provided vital minutes in the void left by injuries to Glen Davis, Shaquille O’Neal and Jermaine O’Neal.

Seems like the Celtics have been answering questions about injuries for the past two years.

Those questions, like the injuries, linger. All those banged-up bigs have forced Green to play power forward more than anyone expected, meaning Paul Pierce isn’t getting as much rest as he should with six weeks remaining in the regular season.

Rajon Rondo is also playing the role of workhorse down the stretch, because nobody else has been able to play the role of backup point guard.

Nate Robinson couldn’t do it so he’s gone. Carlos Arroyo, who went from starting for the Miami Heat to looking for a job in two months, is being given the chance to become that guy.

If he can’t do it, Coach Doc Rivers again will find himself depending on Delonte West to provide meaningful minutes.

Getting West to play any minutes has been a challenge. Between suspensions and injuries, West has managed to play only eight games this season. He expected to play Monday night against the New Jersey Nets but didn’t.

He’s been out for the last six games after spraining his ankle during a walkthrough last month. A walkthrough.

Ainge has been a busy man. It’s mid-March, and Green, Krstic, Arroyo, Sasha Pavlovic and Troy Murphy are still learning the schemes.

It’s rare that a championship contender has this many new faces on the floor, but that’s what Boston has had to deal with in light of all those nagging injuries.

The Celtics aren’t going to win in the postseason based on how the new guys play. Pierce, Rondo, Ray Allen and Kevin Garnett are going to have to be at their best.

From now through mid-April, all these late-season additions are going to have to take it to the finish line of the regular season if the Celtics are going to be ready to go at the starting line of the playoffs.

Tom Caron is the studio host for Red Sox broadcasts on the New England Sports Network. His column appears in the Press Herald on Tuesdays.