From start to finish, the 2018 Red Sox led a charmed life.
After finishing with the best record of any team in the Grapefruit League, the Red Sox sprinted to a 17-2 start. They never fell more than two games out of first all season, never experienced a losing streak longer than three games and held onto first place in the American League East from June 27 through the rest of the season.
They finished with a plus-239 run differential. They led the league in virtually every significant offensive category except home runs.
Which isn't to say that they were "lucky,'' or didn't earn their 108-win season or the championship that followed in October.
There was nothing fluky about the team's record-setting season and nothing was given to them. The Red Sox earned every win, right down to the last one, the Game 5 World Series clincher in Dodger Stadium.
But it was a season in which virtually everything went right.
- With the exception of second baseman Dustin Pedroia, who made a cameo appearance at the end of May for three games then never played again, the team was able to avoid long-term serious injuries to their core players.
- A 29-year-old journeyman, Ryan Brasier, who began the year emailing teams to attend his Arizona tryout, ended the season as one of the most trusted bullpen options.
- Two trade deadline acquisitions -- Nathan Eovaldi and Steve Pearce -- delivered even more than had been hoped and became huge postseason factors, with Eovaldi turning in a marathon relief appearance for the ages and Pearce taking World Series MVP honors.
Now, as the Red Sox begin defense of their ninth title in franchise history and fourth since 2004, and attempt to become the first team this century to win back-to-back championships, there is this bit of cold reality to face down: this year is unlikely to run as smoothly.
The New York Yankees, who won 100 games yet still finished a distant eight games behind the Sox in the division race, have improved their rotation (James Paxton), their bullpen (Adam Ottavino) and their infield depth (Troy Tulowitzki, D.J. LeMahieu).
Other contenders will emerge, too. But for the Red Sox, much of the challenges will come from within.
The Sox have opted to go with an unorthodox -- and in some ways, untested -- bullpen setup. One of the relievers who'll be entrusted with many late-inning leads (Matt Barnes) has exactly two career saves. Brasier, likely to be his tag-team partner in the ninth, has none.
And in addition to Brasier and Barnes graduating to ninth-inning responsibilities and closing duties, the Sox will be asking some middle relievers (Heath Hembree, Brandon Workman) to assume more high-leverage situations.
Some outside the organization wonder how the team will respond if the new bullpen stumbles out of the game.
"For a veteran team, with big expectations, a few blown saves in the first week or two could make things interesting,'' said a talent evaluator who saw a lot of the Sox this spring. "That can wear on a club. Do you get some finger pointing in the clubhouse? Does the front office panic if that happens?''
These are questions the Sox didn't face a year ago, when their blazing start from the outset gave them instant momentum, a sense of confidence and validated the choice of Alex Cora as a first-year manager.
But if the Sox struggle as they figure some things out with the bullpen, it could prove unsettling. And a fast start by the Yankees -- slowed some by injuries as the new season dawns, but the beneficiaries of comfy schedule for the first few weeks -- could put the Sox back on their heels.
If it's determined that the current crop of relievers is insufficient, the organization could be boxed in for a while. It's exceedingly difficult to make trades in the first half of the season, with rival clubs still evaluating their talent on hand and unwilling to unload its roster for fear of alienating their fan bases and wiping out second-half interest.
And while there may be free agent options still available -- Kimbrel, remarkably, remains unsigned -- any such investment will send the Sox over the third and final threshold, making even a modest addition to the roster an expensive proposition.
Meanwhile, should the bullpen experiment fail and the Red Sox eventually go over the top tax threshold for the second straight season, second-guessers will ask why the team didn't just make the same decision months ago and retain Kimbrel -- or acquire a more experienced closing option.
There are other potential pitfalls to consider. With three key members potentially headed to free agency this year (Rick Porcello, Xander Bogaerts and J.D. Martinez) and another two next year (Mookie Betts and Jackie Bradley Jr.), with their uncertain futures serve as a distraction? Will some of the players entering their walk year be guilty of trying too hard in order to enhance their value.
That wasn't an issue a year ago, when Kimbrel was the lone star in his final year of control.
When it comes to handling personalities, maintaining relationships and having a pulse of the clubhouse, Cora appears uniquely suited to put out any fires that could erupt.
But some issues -- injuries and under-performance chief among them -- are beyond his control.
Betts and Martinez enjoyed career seasons, and at their age and given their drive, could replicate or even surpass their remarkable accomplishments from a year ago. But they could also experience drop-offs, the results of which could negatively impact the remainder of the lineup.
Eovaldi has only twice made more than 24 starts in a season; Eduardo Rodriguez never has. By Friday, both Chris Sale and David Price will be 30, with all the potential risk that suggests.
Of course, in returning virtually their entire roster from a record-setting season a year ago, the Red Sox could be as good, or perhaps slightly better.
But it's far more likely that there will be more bumps over the course of a demanding six-month season. How they respond will go a long way toward determining whether the Red Sox are a team for the ages -- or merely another team that couldn't duplicate its success for a second straight season.