BOSTON – Like a shiny new rattle that an infant shakes over and over again to his own wonderment, the Red Sox and their fans are still enthralled by the sensation of defending a World Series title and being in first place in the A.L. East. But even before the Yankees rolled into town with a come-from-behind 8-6 win last night, the Sox had several reasons to be worried. After all, it’s not at all clear whether their ace or their closer can still pitch effectively, and their rivals from the Bronx, despite having struggled all season, now sit a mere 1 1/2 games off the division lead.

Last year, and late in 2003, the Red Sox’ pitching, particularly the bullpen, was an imposing force. This year, it’s been a disaster. The staff’s first-half ERA of 4.84 was the third-worst in the AL, and the bullpen’s 5.64 mark was dead last. Entering last night’s game, opponents had a .289 batting average and .825 OPS against Boston relievers, reason enough for opposing batters to crave the sight of manager Terry Francona taking the ball from his starter.

Alan Embree, who gave up just two runs in 14 innings the last two Octobers, allowed 31 in 35 2/3 innings the first half of 2005. Keith Foulke, who boasted a 0.64 ERA in the 2004 postseason, struggled to a 6.23 ERA in 2005 before finally deciding to have an operation on his left knee. Further confirmation of the Sox’ woes came last night, when ace-turned-closer Curt Schilling gave up Alex Rodriguez’s game-winning homer in the ninth inning.

What has been obvious for weeks received further confirmation last night: The fate of the Red Sox begins and ends with Foulke’s knees and Schilling’s right ankle. A cloud of mystery surrounds Schilling’s condition, with some worried that he may never regain sufficient strength, others thinking that he could return to the rotation later this summer. Foulke is expected back by the middle of August, but his right knee needs an arthroscopy as much as his left. A return to full health this season for both of them? Unlikely – but not out of the question.

Schilling’s experimental stint in the bullpen, which began with failure, will be endlessly scrutinized and analyzed – both by Schilling and the local press – but it should alarm the Red Sox if his stay there lasts more than a few weeks. Schilling is a starter, Foulke a closer; without each in his proper place, the Red Sox have little shot of sticking around into late October.

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The Red Sox can always count on their remarkable offense, which, one through nine, is as potent as anybody else’s in baseball. Entering play last night, they led the majors with a .282 batting average, ranked second with a .357 on-base average, and trailed the Yankees by five runs for the major-league lead. Their superstar nos.3 and 4 hitters, David Ortiz (.314 AVG/.396 OBA/.585 SLG) and Manny Ramirez (.275/.361/.549), combined for 43 homers and 155 RBI in the season’s first half, and Johnny Damon (.343/.386/.473) is second only to Baltimore’s Brian Roberts as the best leadoff hitter in the game. That trio, bolstered by a career year from Jason Varitek and solid hitting by Trot Nixon, give Boston a complete offensive threat unmatched by any other team.

Along the way, the Sox have survived weak hitting from the entire infield. First baseman Kevin Millar has been the biggest disappointment, hitting just .264/.342/.368 with four homers and 32 RBI, numbers better suited for a utility infielder. Second baseman Mark Bellhorn has compiled a frightening load of strikeouts (104), and his .218 batting average and 27 RBI would be, like Millar, unacceptable on most other teams.

On the Red Sox, they are carried over like the balance on a credit-card bill. If those two, along with third baseman Bill Mueller – who has just four homers – and shortstop Edgar Renteria (.272/.327/.387), start to hit as they are capable of doing, the Red Sox should revert to the form that saw them outscore all other teams by a comfortable margin in both 2003 and 2004.

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Great offense, of course, cannot cover up mediocre pitching, which is exactly what the Red Sox have had this year. Matt Clement (10-2, 3.85 ERA) has been the stud in the rotation, and Mike Timlin (1.69 ERA) has done the same in the bullpen, but no one believes the team can thrive for seven months with those two as its best arms.

Where the Red Sox can find additional help is another big question. General Manager Theo Epstein has indicated that he will not be making risky trades for pitchers, which in past years have cost the team top prospects and netted the likes of Bobby Howry, Scott Sauerbeck, and Jeff Suppan. The Sox’ current crop of prospects – shortstop Hanley Ramirez, second baseman Dustin Pedroia, and pitchers Jon Papelbon, Jon Lester, and Anibal Sanchez – are untouchable, according to Epstein. That is wise: The Sox do not want to get stuck in the cycle of the post-2000 Yankees, who began wheeling and dealing away the core of their own farm-produced talent in exchange for expensive veterans.

Submariner Chad Bradford, just acquired from the A’s for grumpy outfielder Jay Payton, is a start to curing the Red Sox’ bullpen woes. The team may have one more deal to make for their bullpen, perhaps someone like struggling Braves closer Danny Kolb. A blockbuster for a starter seems highly unlikely, though, considering the steep asking price for arms like San Francisco’s Jason Schmidt.

Instead, the team is counting on last night’s starter Bronson Arroyo (4.14 ERA), Tim Wakefield (4.05), David Wells (5.00), and Wade Miller (5.03) to eat innings at league-average levels until Schilling is healthy enough to return to the rotation. The Sox are also eyeing their best minor-league arms as mid- to late-summer call-ups for their bullpen, hoping that one of them will catch fire a la Francisco Rodriguez in 2002.That is a long shot, of course, but few credible alternatives exist.

Last year’s World Series triumph marked the birth of a new era for this historically fascinating, frustrating, and exciting franchise. The Red Sox have the talent to win another World Series, but they’ll need a lot of good fortune and good health. If they don’t get lucky, and fail to win it all again, well, that’s how life was for 86 years. It’s nothing to cry about.