PHILADELPHIA—Maybe it’s no big deal.

Andrew Bynum will be back before they know it—with two healthy knees—and the Philadelphia 76ers will go on to have the glistening season many are projecting.

His unexpected three-week precautionary absence due to a bone bruise suffered while recovering from that recent non-invasive Orthokine procedure performed on both his knees in Germany—announced at the start of Media Day here yesterday—will simply be a glitch in the road to their ultimate success.

Certainly that’s what they’d all like to believe.

Or maybe it’s a harbinger of things to come; a reminder that potential danger lurks around every NBA corner. Just when you think it’s all laid out perfectly for you, that’s when the gremlins will get you.

“Things don’t always go the way they’re supposed to,’’ said philosophical fifth-year forward Thaddeus Young, who suddenly finds himself highest in seniority on this completely revamped team.  ”As a team we’ll be able to play without him three weeks, then work him back in.

“The good thing is it’s at the beginning of the season, not the end.’’

Ah, the silver lining.

The Sixers didn’t trade for Andrew Bynum so much for what he’ll be doing in October and November as for what he’ll bring to the table come April, May and perhaps beyond. If he needs a few weeks to rest up, they can live with it.

Just promise them it’s nothing more serious than that.

Bynum, for one, doesn’t seem too concerned. “I’m definitely disappointed because I wanted to be out there,’’ said the franchise’s new centerpiece, who admits to still being overwhelmed by the outpouring of affection from the fans at his introductory press conference back in August.  ”But I’ll do all the walkthroughs, lift weights, do the stretching. Get on the treadmill.

“I definitely feel a lot better.  The Orthokine is definitely working. There hasn’t been swelling in my knees. Kobe (Bryant) told me to go over there and do it. It really helped him out.

“Everybody that has this procedure goes through this, having to get their legs strong and get back out there on the court.”

Feel a little better now, Sixer fans.

Of course until they actually see the big man who grew up some 50 miles from here get on the court and play, no one will really feel at ease. The initial prognosis is for Bynum to avoid all basketball activities the next 21 days. If all goes according to plan that would leave just nine days before the Halloween night opener vs. Andre Iguodala and the Denver Nuggets.

Not much time to get accustomed to things. “It is what it is,’’ shrugged Bynum, the prize off-season acquisition on a team that returns just five players from the 35-31 squad that came agonizingly close to making it to the Eastern Conference finals. “I need to go out and work on my craft.

“I still should be able to do that.  I haven’t had an opportunity to play with these guys.  I’m looking forward to establishing that chemistry. ‘’

That will have to wait for now, as the new-look Sixers will have to at least start out without the big guy. For the returnees, Young, guards Evan Turner and Jrue Holiday, center/power forward Spencer Hawes and second-year man Lavoy Allen, it’s a momentary setback.

They were hoping to pick up where they left off last year, boosted by all those offseason moves bringing a stable full of  shooters—Nick Young, Dorell Wright and Jason Richardson—and a blend of youth mixed with experience into the fold.  Now, while that won’t exactly be put on hold, it will slow what already figured to be a tricky learning process.

Plus, there’s all those expectations from a team that’s never had them and essentially has been playing with house money until now. Royal Ivey, all too familiar what that can do to a team after playing for the Thunder last year, says they simply have to ignore it.

“Don’t worry about expectations,’’ said Ivey, starting his second tour of duty here, with only T. Young and Holiday left from his 2009 club. “Just go day-to-day, continue to work and it’ll come together.

“I know it’s very easy to say, but it’s a long season.  Just put things in perspective and we’ll be fine.’’

Perhaps they will. Perhaps there’s no cause for alarm, something which seems almost inbred in Sixer fans who’ve been longing for a team to fall in love with since Allen Iverson carried Larry Brown’s 2001 team to the Finals. But before the panic begins, a voice of reason suggests some patience might be of value.

“Obviously it’s disappointing,’’ said coach Doug Collins, whose personal disappointment was soothed a bit when owner Josh Harris announced the Sixers have picked up the option year of Collins’ contract, taking him through at least 2014.  ”And no one’s more disappointed than Andrew.

“He’s so chomping at the bit to come in here and live up to all the expectations.  He knows what’s at stake.

“But this is a big guy, 7-2, 300 lbs. We have to err on the side of caution. Kobe told him it (the Orthokine procedure) put five years on his career,  I think that procedure’s going to show a lot of long-term benefits for him.

“Our doctors feel that will be very beneficial for him.’’

The bottom line for Sixers fans then is while it might be premature to plan on a parade down Broad St. yet, don’t tear up your season tickets, either.  Time will tell, of course, where Bynum and the gang stack up behind champion Miami in the East hierarchy.

And while this is clearly an unexpected early setback for a Sixers franchise that didn’t need one, it doesn’t have to be fatal.

At least they sure hope so.

Jon Marks has covered the Philadelphia 76ers from the days of Dr. J and his teammate, Joe Bryant (best known as Kobe’s dad). He has won awards from the Pro Basketball Writer’s Association and North Jersey Press Club.  His other claim to fame is driving Rick Mahorn to a playoff game after missing the team bus. Follow him on Twitter.