After an offseason that included a 149-day NBA lockout; $3 billion worth of concessions by the players; half the Denver Nuggets team fleeing to China, injuries to Paul Pierce, Kevin Garnett and Rajon Rondo (but somehow, not Jermaine O’Neal); a scheduled heart surgery for Jeff Green that will force him to miss the rest of the season; a trade that shipped Glen Davis to Orlando for a similar, yet cheaper and more efficient player; dozens of pointless “All-Star” exhibitions; 9,349 combined lockout columns by Ken Berger, Chris Sheridan and Adrian Wojnarowski; a trade that sent Chris Paul to the Los Angeles Clippers (where it’s unclear whether Donald Sterling will shout racial slurs at Paul whenever he makes a turnover); way too many hockey highlights on SportsCenter; the odd re-signing of Sasha Pavlovic; the curious decision not to re-sign Delonte West; the recovery of Marquis Daniels; a close but ultimately failed pursuit of David West; dozens of Rondo rumors; a phone bill for Danny Ainge that was longer than Yao Ming; Kobe Bryant’s divorce (which, coincidentally or not, coincided with Mad Kobe Bryant emerging after the outrageous Lamar Odom trade); and this sentence, which is probably the longest ever written; Boston Celtics basketball (of the preseason variety) returns today at 1 p.m. when the Celtics visit the Toronto Raptors.

If you got through that sentence (or paragraph, or essay, or novel — whatever you want to call it), I applaud you for having a greater attention span than the average human being. We’ve been through a lot this offseason, as Celtics fans, as NBA fans, as people who hate seeing the SportsCenter Top 10 dominated by slap shots and stick saves, but we’ve persevered and made it to the other side.

For the Celtics, that other side threatens to be oddly mediocre. At the juncture when the David West deal seemed imminent, Danny Ainge was the ultimate wizard and dreams of an 18th banner danced the macarena inside my head. Since then, West signed in Indiana, the Celtics re-signed Sasha Pavlovic (why?), Jermaine O’Neal was named the hypothetical MVP of training camp (can’t tell whether that’s a good thing or bad thing), Jeff Green learned that he requires heart surgery that will force him to miss the rest of the season, and three-fifths of Boston’s starting five has missed preseason practices due to injury. Boston’s bench no longer inspires fear (at least not to opposing teams), its starting five has players of ages 33, 34, 35 and 36, Ainge never did sign a backup center, and oh, in case you forgot, Boston’s backup wings are E’Twaun Moore (an unproven rookie second-rounder), Avery Bradley (a sushi-raw second-year pro who needs a ton of work), Marquis Daniels (coming off spinal cord surgery) and Sasha Pavlovic (who hasn’t been a decent player since Lebron James was universally beloved and considered clutch). My dreams of an 18th banner have been hijacked by an army of question marks.

There is still a lot to like (or love) about these Boston Celtics. Rajon Rondo has made huge strides each season since being drafted, by all accounts worked his ass off this offseason, and should have a chip on his shoulder the size of Michael Sweetney after being mentioned in so many rumors. Paul Pierce can still score against anyone, Ray Allen is still ageless, and Kevin Garnett — at least on the nights his knees work like they’re supposed to — still affects a game on both ends like nobody else (this side of Dwight Howard) in the NBA. Boston’s bench, even if it won’t provide much shooting and doesn’t include a center, mixes intriguing young prospects with a crop of veterans who know their role and should be more consistent than last season’s eccentric bench mob.

Yet the Celtics — I often return to this, which sucks — looked like a team of the past against Miami in the 2011 playoffs, like a team that needed to add significant pieces to have another shot at contending. Ainge needed to seriously upgrade the bench to stem off the inevitable step or two that Pierce, Allen and Garnett will lose, not to mention the dozens of injuries sure to affect one of the league’s most elderly lineups. It wasn’t entirely Ainge’s fault that Boston’s bench now holds so many ifs: Nobody could have foreseen Green’s medical issues, building a bench almost entirely from scratch with no money to work with is like trying to prod Earl Boykins into snatching 10 rebounds per game, and the market became a weird one in which Marcus Thornton was paid $31 million and Kwame Brown will earn $7 million for one season. In a market like that, adding significant players using just the veteran’s minimum is difficult, which I suppose is why it especially stung that Delonte West accepted a minimum deal elsewhere. (Note: I’m still convinced there are underlying issues that caused Boston not to aggressively pursue West. Because from a basketball standpoint, he’s far more talented than Keyon Dooling.)

I enter this season with hope, but dim hope, hope that’s an island surrounded on all sides by worries. The way I see it is this: It’s possible for the Celtics to win an 18th banner this season, but almost everything — and I don’t just mean almost everything under their control — will have to go right. Rondo needs to take the next step. The Big Three needs to enter the playoffs at full strength. JO (gulp) can’t miss half the season due to injury. JaJuan Johnson and/or E’Twaun Moore need to establish themselves as legitimate rotation players. Marquis Daniels needs to prove he’s the same player after spinal surgery as he was before it. Brandon Bass needs to be what we think he is, an upgrade to Glen Davis. Doc Rivers needs to control minutes perfectly to preserve his big guns for the playoffs, but also to establish a rhythm during the season so Boston doesn’t fall apart like it has the past two regular seasons.

Any crew of junkyard dogs that has three first-ballot Hall of Famers and a 25-year old All-Star point guard will be a bitch to oust from the playoffs. Nobody wants to meet the Celtics in round one or round two, even if the C’s enter the playoffs walking with a limp and spitting up blood during timeouts. But an 18th banner seems like a longshot. It’s a possibility, but it would take an other-worldy effort during which the stars are perfectly aligned in the sky.

The quest begins today at 1 p.m. It’s just pre-season, but after all that transpired during this extended offseason, the thought of Celtics basketball — not to mention the sound of Tommy Heinsohn’s voice — makes me giddy.