It will take some time for the fallout from one of the biggest trades in Phillies history to settle, for all the implications to be digested, for all the what-ifs to sort themselves out.

In the immediate aftermath of saying hello to Roy Halladay and goodbye to Cliff Lee and a trio of well-regarded prospects yesterday, though, a couple of observations may be ventured.

The top of the Phillies' 2010 rotation is better, but more by a matter of degrees than light years.

And when the merry-go-round finally stopped spinning yesterday, the bigger impact may have been on the fifth starter than on the slot occupied by the ace.

The Phillies, of course, pursued Halladay before the trading deadline last July. They ended up getting Lee instead. This was the analysis at the time:

"At the same time, Cliff Lee shouldn't be viewed as some sort of booby prize. The news . . . is better than that. The difference between the two isn't enough to drive a tractor-trailer through. A compact, or even a midsize maybe. But not a big rig."

That still holds true.

Halladay is one of the very best pitchers in baseball. But the Phillies went to the World Series with Lee last season and the fact that they lost to the Yankees in six games was hardly Lee's fault. He was terrific in the postseason, 4-0 with a 1.56 earned run average.

Where Halladay does have a huge advantage beyond next season is that he agreed to an extension that allows the Phillies to control his contract through 2014. Maybe Lee would have agreed to a similar deal. Maybe he wouldn't have. But Halladay did.

General manager Ruben Amaro Jr. said he couldn't say how much better the Phillies will be next season with Halladay instead of Lee as their No. 1 starter.

What's really dicey is figuring out who will follow Cole Hamels, Joe Blanton and J.A. Happ. The candidates at the moment are 47-year-old lefthander Jamie Moyer, who is coming off multiple surgeries, and unproven Kyle Kendrick.

There was every reason to believe that, had the Phillies been in a bind in the latter part of the season that 2006 No. 1 draft choice Kyle Drabek would have the inside track to step in.

Now that Drabek has been traded to the Blue Jays, the Phillies have dangerously few options.

"It is concerning. I've talked about not having a whole lot of depth in our rotation. I guess it's going to be my job to help develop or find pitchers who will give us some more depth," Amaro said.

He mentioned two pitchers who came from Seattle as part of the three-cornered transaction.

"Maybe that comes internally. Maybe it's a guy like [Phillippe] Aumont who can give us some depth. We're still not sure whether we're going to have him in the bullpen or the rotation. Maybe it's a guy like [Juan] Ramirez who steps up and matures," he said. "Maybe it's a guy like [Phillies 2007 No. 1 pick Joe] Savery, who steps up and does some things. We're going to have to get creative to try to create some depth there."

Or maybe the Phillies will once again find themselves trying to make a deal for pitching at the deadline.

"It is a risk. There's no question about it," Amaro said. "There's no question that our pitching could be hurt because you can never have enough starting pitching. You can never have enough pitching in general. We have moved some of the depth out of our system.

"We think we can replenish it with depth that's a little further away. That with a horse like this it was worth the risk."

It takes years to fully assess trades, especially ones as complex as this. It will probably take until at least the end of next season to begin to judge yesterday's blockbuster.