For all the fretting about the health and future of Roy Halladay, it’s worth noting that a repeat of his disappointing 2012 campaign wouldn’t be a kiss of death.

Last season, getting just a 4.49 ERA and 11-8 record from their No. 2 starter, the Phillies missed the playoffs by just seven games. Using Halladay’s season win percentage, he’d have won 4.6 of 7 projected starts over the seven weeks he spent on the DL. Given the struggles of the bullpen – the Phillies lost 17 games despite leading in the seventh or later, 13 games despite leading in the eighth or later – and improvements there since, much of the difference could be made up there.

A healthy Ryan Howard and Chase Utley should bridge the rest of the gap, and then some.

What the Phillies can’t afford from Halladay, though, is regression.

Last year, Phillies starters ranked just seventh in ERA – in the National League. That they ranked just eighth in wins with 56 was much a credit to that no-decision-happy bullpen. But Phillies starters last year were charged with 54 losses, sixth worst in the NL, despite a lineup that provided a just-about-average 684 runs scored, good for eighth in the league.

It’s not like Phillies starters can play the bad luck card, either. The staff ranked fourth-best in the NL in fielding-independent pitching, a metric that accounts for poor defense, but their opponents’ .298 batting average on balls in play (sixth-worst in NL) suggest it’s more a matter of shoddy fielding – something that might prove problematic this year, too – than crappy luck.

The Phillies hope that mid-to-late season improvement from Kyle Kendrick would compensate for Halladay, whatever he is this year, but there’s reason to wonder whether his 2012 season is sustainable. Kendrick worked a 21 2/3 scoreless inning streak last summer as a starter – he also went 15 innings without allowing a run in one start and seven relief appearances in July – but much of that success was predicated on his changeup, a pitch he’s spent a few years developing since being sent down to the minors in 2010, and mastered only recently.

Has Kendrick simply been tricking opposing batters? Will they catch up?

And as iffy as Joe Blanton was before a midseason trade to the Dodgers, his 4.59 ERA in 133 1/3 innings last year saddled that of the staff as much as did Halladay’s.

John Lannan, signed over the winter and later slotted to be their No. 5 starter, has had an ERA under 4.00 in three of six big-league seasons and just one (a 4.65 in 2010) higher than Blanton’s in 2012. Even then, there’s a reason he started the Nationals’ 98-win season in the minors after a career best 3.70 ERA in 2011. Simply, it’s highly unlikely Lannan will be enough to compensate for further slippage from Halladay. Few are.

In fact, if Halladay were to be any poorer than he was in 2012, there likely wouldn’t be room in the rotation for him altogether. Last year, just 95 pitchers threw 150 innings or more – the ones teams felt they could rely on, even if only for back-of-the-rotation work. About three per team.

Of those, Halladay’s ERA ranked 76th, worse than Barry Zito (66), Kevin Millwood (69), Ricky Nolasco (74), and Tommy Hanson (75). What would be worse? Eating $20 million by pushing the guy earning it to the side? Or stubbornly using him on principle, and getting buried by it?

The Phillies were likely to rely on a sixth (or seventh or eighth) starter for about 10 or so starts next season to begin with. If Halladay’s slide continues, or if he's injured again, that would likely mean heavy reliance on Aaron Cook (5.54 ERA the last three seasons), Jonathan Pettibone, 22, Adam Morgan, 23, or Ethan Martin, 24. Of the three minor-league twentysomethings, only Pettibone has pitched above Double-A, and even then, he’s only appeared in seven games as a starter.

Last season left many wondering whether he could ever be the 2002-2011 Halladay again. This spring – seven runs in 2 2/3 innings against the Tigers with four walks and a hit batter, one inning and 25 pitches against the Orioles five days later, retired just 7 of 18 batters with seven hits, two walks and a HBP, charged with just two earned runs but was pulled with the bases loaded in a minor league start Saturday – conjures much of the same about even the 2012 Doc.

For good reason. Because the Phillies can’t afford much worse.