CLEARWATER, Fla. -- With three weeks to go before opening day and the roster apparently set, there’s an important question still looming over this forthcoming Phillies season. In order to answer it, you must first consider a question much broader in nature.

Here, in the year 2019, what is it that a team needs from its rotation in order to consider itself a legitimate contender?

At first glance, the Phillies in their present form would seem to fall short of where intuition suggests that bar is. Even if Jake Arrieta, the No. 2 starter behind Aaron Nola, pauses or reverses the regression in his performance over the last few seasons, to have confidence in the final three spots in the rotation requires a faith in the unseen. Nick Pivetta, who made his Grapefruit League debut Tuesday, finished 2018 with a 4.77 ERA that was well north of the typical mark of a first-division No. 3 starter. Same goes for Vince Velasquez, who posted a 4.85 ERA in 146 ⅔ innings.

On Tuesday, I asked Gabe Kapler whether it was possible for his team to be the team it is hoping to be if Pivetta and Velasquez replicate their production of last season, or if the Phillies are counting on both to take steps forward.

“I’m not sure it is either-or, and I’m not even sure it is that black-and-white,” the manager said. “We think that if Pivetta continues to develop, if Velasquez continues to develop, [Zack] Eflin continues to develop, Jake is already demonstrating some signs that he can not just have a year that was better than last year but maybe one of the better years of his career — if all of those things happen, we’re going to win a lot of games, and that’s what we’re striving toward.”

That’s a lot of ifs, and history suggests that the more of them a team has to tell itself at this stage of spring training, the greater the chance it ends up looking back from a certain juncture in time and realizing that the seeds of defeat were sown long before. For all of the hullabaloo surrounding the additions of Bryce Harper and J.T. Realmuto, it’s worth noting that the Phillies’ first order of business this offseason was the pursuit of a top-of-the-rotation arm, which fell short when Patrick Corbin instead signed with the Nationals.

At the moment, the pickings on the free-agent market are slim. You can make a case that 31-year-old lefty Dallas Keuchel would dramatically improve the Phillies’ chances, but it’s hard to argue that the immediate reward would be worth the risk of a long-term deal.

“I think it’s a big vote of confidence, it really is, when you don’t bring in anybody else,” Pivetta said after his outing on Tuesday. “And it’s going to show when we really ride through that [August] stretch into September and we’re still staying strong that whole entire time.”

The question remains: Is that confidence enough?

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There’s no doubt that this is a much improved team, and that the additions it has made to the bullpen and the lineup will lighten the load the rotation must carry. But for all the money the front office has lavished on this roster, the starting pitching still looks disconcertingly similar to how it did at the end of last season, when it was the primary factor in the Phillies’ precipitous fall out of the playoff race. They lost seven of Pivetta’s last eight starts as the right-hander averaged less than five innings per outing with a 6.10 ERA during that stretch. Velasquez, meanwhile, lasted longer than four innings in just two of his final nine starts, posting an 8.45 ERA while allowing runners to reach base at a .418 clip.

The flip side is that, up until those final weeks, both Pivetta and Velasquez were giving the Phillies the sort of production that can work in a modern rotation. Among the NL’s five playoff teams in 2018, there was only one starter who finished the regular season with 200-plus innings pitched. In all of major league baseball, there were just 13 such players, the fewest of any non-strike-shortened season in the integration era. (From 2010-15, the average season had 35 starters reach 200.)

Consider, too, the workload of starting pitching staffs that qualified for the postseason: In 2015, those rotations accounted for 66 percent of their teams’ innings pitched. In the three years since, that number has fallen to 65 percent, and then to 63.3 percent, and then, last season, to a mere 61.4 percent.

When the Astros won the World Series in 2017, they entered the season with a rotation less accomplished than the one the Phillies currently boast. Brad Peacock entered the season with a 4.57 ERA in 263⅔ career innings, and Mike Fiers would finish 2017 with a 5.22 ERA in a team-high 153⅓ innings. Two years earlier, the Royals won with a rotation that backed Edinson Volquez and Yordano Ventura with Danny Duffy (4.43 FIP) and a couple of 36-year-old veterans (Jeremy Guthrie, Chris Young).

In both cases, the recipe for success combined a stacked lineup with a lock-down bullpen and, in the Astros’ case, the trade-deadline addition of Justin Verlander.

There’s a plausible scenario in which even modest improvements by Pivetta and Velasquez would leave the Phillies in position to be an Astros/Royals sort of team. At this point, that seems to be their best hope.