By A.Sherrod Blakely
CSNNE.com
WALTHAMWhen the season began for the Boston Celtics, there was a lot of talk about their shrinking window of opportunity.
Well, there have been plenty of opportunities . . . for the Celtics' bench players.
Injuries to key starters has left coach Doc Rivers little choice but to call upon his reserves more often than anticipated.
He'll continue to do so with Shaquille O'Neal out for Tuesday night's game against Cleveland, and possibly some -- or even all -- of the team's upcoming West Coast trip that begins Thursday in Portland.
"He'll miss Tuesday -- unless something happens where it's a miracle," Rivers said of O'Neal. "And the flight to Portland is a difficult flight; it's seven hours or whatever. I personally think that would be a tough game for O'Neal to play in. I think after that, he's pretty much available."
No O'Neal means more Semih Erden, who will likely get the starting nod.
Boston Celtics
The 7-foot rookie from Turkey has averaged eight points and 4.8 rebounds in five starts this season.
With increased playing time, Erden has steadily improved.
In Boston's 85-83 loss to Washington, Erden grabbed a career-high 11 rebounds.
The night before that, he scored a career-high 14 points in Boston's win over Utah.
With O'Neal having already missed 10 games this season, it makes you wonder if the Celtics need to give serious thought to limiting his play moving forward.
"We've done that in some ways," Rivers said. "We've pretty much kept his minutes down. We had the one 35-minute burst. And don't forget, we're bringing Perk back."
Ah yes, Kendrick Perkins.
He continues to impress Rivers and his teammates during live practices, with a return date tentatively scheduled for Feb. 4 versus Dallas.
His return will certainly allow Rivers to rely less on O'Neal at the center position.
But with guys continuing to be in and out of the lineup because of injuries and very little time to practice, it has been difficult for the second unit to develop the kind of flow they will need later in the season and into the playoffs.
"It's tough. It's tougher than even last year in that regard, because of the continuity," Rivers said. "We do a lot of skeleton stuff over and over again, which is extremely boring. We've been able to keep our rhythm somehow."
During those skeleton drills, because of the lack of bodies available, guys often find themselves practicing at a position that they are surely not likely to play in a game.
For example, Glen Davis spent time on Monday practicing at the small forward position.
"He enjoyed it," Rivers said. "He thought he could shoot every time, like Paul Pierce."
Clearly, Davis is not a small forward.
But then again, 6-6 forward Marquis Daniels is not a power forward, either, but he has seen some time at that position this season.
All the Celtics have to be ready, to play any and every position.
Because with all the injuries they have had this season, there's no telling when an opportunity to play will present itself.
A. Sherrod Blakely can be reached atsblakely@comcastsportsnet.com.Follow Sherrod on Twitter at http:twitter.comsherrodbcsn