The Christmas Day loss to the Lakers was understandable. And maybe even the next night’s loss to the Warriors was forgivable, since it the second of back-to-back games and Oakland is always a tough place to play. But what about consecutive losses to the Knicks and the Bobcats, each with a day’s rest beforehand? After racing out to the best start in league history, the Celtics are now 2-5 in their last seven, and have lost back-to-back games to teams with a combined record of 26-42. Ouch.

It’s tough to be the defending champs, because every night you’re going to get your opponent’s maximum effort. It’s also important to note that all five of those losses were road games, and it can be tough to win on the road in the NBA, especially when you have a big bull’s eye painted on your back.

A quick look at the Celtics’ season stats reveals a few things:

1. Other than Eddie House, they don’t have a legitimate three-point threat on their bench. This is an area where they miss James Posey (along with what he brought to the table defensively).

2. Glen Davis is shooting 37% from the field, which is absolutely dreadful for a power forward. Despite bigger minutes, his points and rebounds are down. Not good.

3. Rajon Rondo and Kendrick Perkins are holding up to their end of the deal. Rondo is averaging 11.1 points, 7.6 assists and 4.9 rebounds a game, and he’s fourth in the league in steals. He is quickly developing into one of the best all-around point guards in the league. Perkins hasn’t made as big of a leap, but he’s a few minutes away from averaging a double-double. Right now he’s at 8.9 points and 8.5 rebounds per contest.

Given how important James Posey was to the Celtics’ title run, we knew heading into the season that it was a big risk to let the Hornets sign him away. He brought solid defense and good three-point shooting, which are two things that are lacking on the Boston bench right now. The C’s are toying with the idea of bringing Stephon Marbury in for a trial run (if he ever agrees to a buyout with the Knicks), and he would provide some long-range punch off the bench. I don’t see a lot of other options for the Celtics, considering they don’t have a substantial expiring contract or tradeable players. Garnett and Pierce are untouchable, and the team can’t do without Ray Ray’s outside shooting. Rondo is too good and he would leave a gaping hole at point guard, and the same goes for Perkins in the middle. What are the C’s going to get for House, Tony Allen or Glen Davis? Leon Powe would be good trade bait, but the Celtics need his toughness and rebounding off the bench. Besides, it’s doubtful that Danny Ainge would make any major changes to this group since it got them to the Promised Land last season.

I don’t think this 2-5 stretch is a sign that the Celtics aren’t for real. They are. The NBA season is a grind and they’ll be there at the end. It’s going to be interesting to see how they play at home tonight against a good Houston team and then on Friday at Cleveland.

Thursday (1/8) Update: The Rockets did indeed beat the Celtics in Boston.