BOSTON — Thanks to the injury to Josh Beckett, the Red Sox’ starting rotation was already in a state of flux.

Now, with inclement weather forcing the postponement of two games in the last four days, the potential for chaos exists.

Things were further complicated yesterday by a rainout in the opener of the Sox’ weekend interleague series with the Atlanta Braves. The two clubs will try a day-night doubleheader today (1:05 and 7:35 p.m.) that will necessitate additional juggling.

Today’s first game will be handled by Daisuke Matsuzaka, in his original spot, opposed by Atlanta’s Anthony Lerew. The nightcap will feature Devern Hansack, last night’s scheduled starter, matched against John Smoltz.

Beyond that, the Sox’ pitching plans are officially unclear. The team has yet to announce a starter for tomorrow, though it’s widely assumed that lefty Kason Gabbard will be recalled from Triple A Pawtucket for the assignment.

One logical explanation for the delay: Hansack could be optioned back to Pawtucket after tonight’s start to make room for Gabbard. Until Hansack’s start is complete and the transaction is necessary, there’s no need for the Red Sox to tip their hand.

But with uncertain weather in the region today, there’s no guarantee that the Sox and Braves will succeed in completing their separate-admission doubleheader.

That, in turn, will require the teams to attempt another day-nighter tomorrow, since this is the only visit by Atlanta to Boston this season.

(After tomorrow, the teams share just one common off-day, Sept. 13, for the remainder of the season, and the Braves have indicated little willingness to return to Boston for a makeup game so late in the season.)

If the teams can’t get the entire three-game set in before tomorrow night, the Sox’ need for Gabbard is eliminated, since an abbreviated series would require just two starters — Matsuzaka and Hansack.

“We can’t control the weather,” said manager Terry Francona yesterday after news of the postponement. “We’ve tried and we can’t figure it out.”

As uncertain as the immediate rotation may be, the Sox have little to complain about when it comes to starting pitching. Entering yesterday, their starters sported a 3.57 ERA, third best in the American League.

Boston’s starters are also among the league leaders in innings pitched (second), strikeouts (second), batting-average against (third), strikeout-to-walk ratio (second) and strikeouts-per-nine-innings (first).

Even the recent loss of Beckett shouldn’t be catastrophic, given the Sox’ improved organizational depth.

Last summer, when injuries struck Curt Schilling, Tim Wakefield and David Wells, the Sox were forced to take the likes of Jason Johnson and Kevin Jarvis off the scrap heap.

This year, Hansack and Gabbard have performed well enough at Triple A to warrant an opportunity, and have had some success in their limited exposure to the big leagues.

Gabbard is 3-1 with a 2.75 ERA in eight starts for the PawSox, while Hansack is 1-4 with a 3.89 ERA and 37 strikeouts in 34 2/3 innings. Moreover, the two have been in the organization long enough to be comfortable.

“They know about throwing over (to first), first-and-third situations, they know the catchers,” said Francona. “This isn’t something we’re going over with them right before they go out to pitch, and that allows them to go out and pitch their games.”

Hansack and Gabbard, both of whom spent most of spring training in the major-league camp, are not unfamiliar to Jason Varitek and Doug Mirabelli, making the transition smoother.

“In spring training,” said Francona. “we make sure that both catchers catch everybody, so they’re not (caught off guard during the season).”

Regardless of how the rest of the weekend plays out, the Sox have set their rotation for the three-game showdown in New York against the Yankees, which begins Monday.

The Sox will pitch Wakefield on Monday, Julian Tavarez on Tuesday and Schilling on Wednesday, enabling them to pitch three of their top four starters in the series.

smcadam@projo.com