Oswalt's likely departure changes dynamic of Phillies rotation

The Phillies, of course, will still have a formidable rotation even if it no longer has a catchy nickname - R1 C2 just doesn't work - that requires a spring-training news conference before any meaningful pitches are thrown. The Who could still bring it for a while after Keith Moon's demise, and there is every reason to believe the trio of Lee, Roy Halladay, and Cole Hamels will continue to rock the National League in 2012.

The rotation dynamic, however, has changed, with the biggest difference being depth. The most beautiful thing about having four aces (nobody ever really bought into the idea that Joe Blanton was a fifth ace, did they?) was that if one of them got hurt, there would still be three remaining. That's more than enough to win a lot of regular-season baseball games and even most postseason series.

Should one of the top three go down in 2012, the rotation is not nearly as intimidating, and, unless the offense improves, it could be a difficult hurdle to overcome. When Blanton first joined the Phillies in 2008, the offense had enough firepower to overcome his plus-four ERA. The Phillies went 43-29 in his starts from 2008 through 2010 even though he had a 4.35 ERA.

By comparison, the Phillies were only 11-12 in Oswalt's starts last season despite the righthander's having a respectable 3.69 ERA. The team was 7-8 in Kyle Kendrick's 15 starts even though the underappreciated righthander had an impressive 3.14 ERA in those games.

Rookie Vance Worley, of course, was the true fourth ace last season while Oswalt dealt with his back issues. But it's one thing to produce when nobody was expecting much and a very different thing to do so when you are being counted upon.

Worley went into last season at No. 7 on the rotation depth chart. Unless something changes, he'll likely arrive in Clearwater, Fla., this February as the fourth starter. There's some serious pressure involved in rotation elevation, and everybody knows that hitters make adjustments the more they see a pitcher.

We may have seen some of that in the final two months last season, when Worley posted a 3.98 ERA and allowed more hits than innings pitched. Worley logged a career-high 1821/3 innings last season, so if he wants to be considered a true ace, he has work to do in that department, too. J.A. Happ is recent proof that a great rookie year does not necessarily translate into a great career.

All indications after the postseason and his brief stint in the Florida Instructional League were that Blanton is recovered from the elbow injury that cost him most of the 2011 season, but the true test will not come until he is pitching every fifth day. It will be even more important in 2012 that he resembles something closer to a fifth ace than some guy who did not belong at all those spring-training photo shoots with the other four guys.

Kendrick, meanwhile, is going to be more important than ever as the swing man of the staff.

Less than a year after celebrating the advent of Four Aces, the Phillies are down a man, and that means a lot of things have changed.

Contact staff writer Bob Brookover

at bbrookover@phillynews.com or @brookob on Twitter.