Growing pains? Or growing worried?

Six games and a little less than two weeks into the regular season, let's crack open the mailbag and check the pulse of Celtics fans after a 3-3 start to the new campaign:

Q: TIME TO PANIC! -- Roberto (New York City)

A: For those first-time visitors to the 'bag, Roberto is our resident thermometer. He's a die-hard Celtics fan who gets swept up in the highs and lows of the season and offers emotional outbursts while riding the roller coaster. To be fair, this letter landed back after Boston dropped its home-opener to the Bucks, falling to 0-2 on the season. Boston has prevailed in three of its last four -- maybe not decisively, but wins are wins -- and the mercury is receding on the panic meters of most fans (maybe even Roberto, too). But our friend is hardly the only one leery of the Celtics' inconsistent start.

Q: Simple question, but a valid one: What's more concerning right now, the lack of defense or the inability to put up points? -- Nick (Salem, Mass.)

A: Boston's troubles with interior defense -- a direct offshoot of breakdowns in pick-and-roll coverage -- are probably the most maddening thing at the moment (see last night's Samuel Dalembert first-quarter dunk party). But it's hard to imagine that the Celtics won't find their way defensively -- that's their bread and butter. The team's inconsistent offense, particularly when either Kevin Garnett or Rajon Rondo are off the floor, is a bit more worrisome. Boston's offensive numbers are surprisingly solid so far (0.934 points per play; sixth in the league overall, according to Synergy Sports), but it's clear the offense has been out of sync at times and Boston's new faces are still trying to figure out how they fit in.

Q: Now that Jeff Green has come to life, when will it be Courtney Lee's turn? He is taking high-quality shots but they just won't seem to fall. Is this just something that will work itself out? -- Seth (Tulsa, Okla.)

A: Since making 5 of 6 shots in the season-opener, Lee is 8 of 25 shooting overall and 1 of 11 beyond the 3-point arc. A career 43.9 percent shooter, Lee has proven to be streaky at times, but he's averaged 40-plus percent from 3-point land the past two seasons, so his inability to knock down triples -- particularly with how open he's been -- is somewhat concerning. Rivers has implored him to be a "ready" shooter, meaning he has to knock down those open looks when opponents collapse on Boston's stars. The good news: Lee's defense has been solid (like the rest of the team, he simply needs to do a better job of getting back in transition). The Celtics can afford to let him work through the shooting woes if he can maintain his defensive presence (0.608 points per play; 89th percentile, according to Synergy).

Q: Why do people insist on Jared Sullinger playing big minutes on this team? He's a decent rebounder, but rookies very rarely have a positive impact on the court their first year. Sullinger's defense and scoring ability are nowhere near NBA-level at the moment. -- Jun (New York City)

A: I thought Sullinger blended well with the first unit during his two starts this past week. I'm not saying he's ready to be a full-time starter, but he offers Doc Rivers a little bit of flexibility with his big-man rotations. One thing is undeniable, the Celtics are a much better rebounding team when Sullinger is on the court. Boston is 4.5 rebounds better per 48 minutes when Sullinger is in the game. Sullinger is also an excellent passer and helps create open looks with ball movement. Yes, his offensive game is limited to cuts and putbacks at this early stage of his career, and he's still learning to play NBA defense, but he's helping this team and adding a much-needed skill set up front.

Q: Will Sullinger ultimately be a more valuable player to the Celtics than Brandon Bass at some point during the season? -- Sam (Boston)

A: I don't think there's any reason to have to pick who will be more valuable, but let's just say that if Sullinger can contribute on a Bass-like level by the end of the season, that's a good thing for Boston. While Bass' contributions sometimes get overlooked, don't discredit his chemistry with the Celtics' core and the success he had with the first unit the second half of last season. Bass' ability to stretch the floor offensively and be a stout defender alongside Garnett at the other end has worked out nicely for Boston. Sullinger's talents are a bit different, but he and Bass complement each other nicely.

Q: With more minutes for Chris Wilcox, are we seeing Rivers move away from his small-ball lineups that weren't really working in the first five games? -- Andrew (Evanston, Ill.)

A: Until Jason Collins and Darko Milicic get unglued from the bench, Boston is still operating small, even with Wilcox on the floor. What Wilcox is changing is the energy. He has realized he's at his best when he's going full-throttle, even over short bursts of playing time while he gets his conditioning right. Wilcox is hitting the glass hard and utilizing his athleticism to get out in transition (where Rajon Rondo is finding him on the move). The Celtics need to get Sullinger to play with the same sort of motor that Wilcox is operating with and they will have a very productive mix at the power forward spot.

Q: What happened to Milicic? He looked as if he would play a big role on this team. What happened? -- Eric (Cranston R.I.)

A: There are a couple things at work against Milicic at the moment: (1) He had a wrist injury that took away key reps at the end of the exhibition season and (2) The schedule has featured almost exclusively small-ball teams at the start of the year, forcing Boston away from its biggest lineups. In an Atlantic Division that doesn't lack for size, Milicic and Collins will get playing time. There simply hasn't been much of an opportunity so far, particularly in close games, in which the Celtics have leaned on their core rotation players.

Q: What's the biggest surprise to you -- on the positive side -- so far this season for Boston? -- Andrew (Manhattan Beach, Calif.)

A: Wilcox's emergence the last three games has been a really nice boost for the Celtics, but I'm also surprised at what Leandro Barbosa has been able to provide. Without the benefit of camp or the exhibition season, he's still finding a way to provide an offensive jolt when he's not he court. Sure, he's cooled from that opening-night outburst in Miami, but his speed will help this team at times. And you didn't ask, so I'll ask myself ...

Q: Biggest negative surprise so far this season? -- Chris (Auburn, Mass.)

A: Garnett has allowed 62 points over 67 defensive plays, a staggering 0.925 points per play. According to Synergy, that ranks Garnett in the 30th percentile among all NBA players and he grades out as "below average." This isn't like last year, when Garnett looked a step slow early in the season. As the Celtics get feasted upon inside, Garnett's individual numbers have been an eyesore. Like the rest of the defense, you figure he'll turn that around, but it's staggering to see how bad the numbers are this early. Boston as a whole is allowing 0.927 points per play, ranking 22nd in the league. One thing that's not a surprise watching them: Their transition defense was dead last entering Sunday's action allowing 120 points in 77 transition plays (1.558 points per play).

Q: So 34 out of 35 experts pick Miami to win the East. Are you sure your pick is not just a homer pick? In the season-opener, it was clear which team is superior, even with LeBron James playing barely a minute in the fourth quarter. Granted, one game a season does not make. I'm just curious why you -- and only you -- thinks the Celtics will get past the Heat. -- Al (Miami, Fla.)

A: Sure, my Celtics-Lakers Finals pick isn't looking too smart right now (who are we kidding? It looks insane). But I'm confident both teams will find their way and be in the mix when it matters. As for picking Boston over Miami, I simply think the Celtics have potential to be much more talented than a year ago when they pushed the Heat to the brink. I'll drink the green Kool-Aid and believe that it's going to take time for this team to sort itself out, particularly integrating all the new faces and defining player roles. I am surprised Boston hasn't played better with all the individual talent it has, but it goes to show that it takes time to get things right together in this league. Heck, Miami went through its own growing pains. Let's revisit the conversation in a couple months and see if Boston comes together, or whether my prediction falls apart. If nothing else, I still believe there's a great chance that we see another Celtics-Heat battle in the conference finals.