It appears that the Phillies have reorganized their rotation in recent weeks, outing 25-year-old-righty Vance Worley and inning 28-year-old lefty John Lannan.

So who’s better — Lannan or Worley? It’s hard to know who will fare better in 2013, and the issue is complicated because Lannan is (almost exactly) three years older, but it’s hard to make the case that Lannan has been better than Worley in the time they’ve spent in the majors.

Here are some of their numbers for their careers, including Lannan’s combined numbers through his age 25 season (Worley just finished his age 25 season):

Age

IP

ERA

Rat

bWAR

fWAR

H/9

BB/9

HR/9

SO/9

Worley ’10

23

13

1.38

0.82

0.5

0.2

5.5

2.8

0.7

8.3

Worley ’11

24

131.7

3.01

1.23

3.2

2.4

7.9

3.1

0.7

8.1

Worley ’12

25

133

4.20

1.51

0.7

1.9

10.4

3.2

0.8

7.2

Total

-

277.7

3.50

1.35

4.4

4.5

9.0

3.1

0.7

7.7

Age

IP

ERA

Rat

bWAR

fWAR

H/9

BB/9

HR/9

SO/9

Lannan ’07

22

34.7

4.15

1.53

0.4

0.0

9.3

4.4

0.8

2.6

Lannan ’08

23

182

3.91

134

2.5

1.2

8.5

3.6

1.1

5.8

Lannan ’09

24

206.3

3.88

1.35

3.1

1.4

9.2

3.0

1.0

3.9

Lannan ’10

25

143.3

4.65

1.56

-0.1

1.2

11.0

3.1

0.9

4.5

Thru 25

-

566.3

4.10

1.41

5.9

3.8

9.4

3.3

1.0

4.6

Lannan ’11

26

184.7

3.70

1.46

0.8

1.3

9.5

3.7

0.7

5.2

Lannan ’12

27

32.7

4.13

1.44

0.3

0.5

9.1

3.9

0.0

4.7

Total

-

783.7

4.01

1.42

7.0

5.7

9.4

3.4

0.9

4.7

Through their age 25 seasons, Lannan had thrown far more innings in the majors than Worley. He had thrown 566 1/3 innings through the end of the 2010 season while Worley has still thrown just 277 2/3 for his career.

In just about every other way, though, Worley has been better. Through their age 25 seasons, Worley has a better ERA, has thrown to a lower ratio, allowing fewer hits, walks and home runs per nine innings while striking out batters at a higher rate. All of those things are also true if you compare the career numbers of the two.

Worley has also had the best year by WAR. Using both Baseball-Reference and FanGraph’s calculations of WAR, the best season either of the two has had to date is Worley’s 2011 performance. On the other hand, Lannan’s 2009 was almost as good and Lannan has had two very good seasons, 2008 and 2009, while Worley has only had one.

Notably, Lannan’s two best seasons came before his age 25 year. Over the last three years, he’s started 64 games and thrown to a 4.12 ERA with a 1.50 ratio, allowing 402 hits in 360 innings while opponents have hit .284 against him. The 4.12 ERA and 1.50 ratio for Lannan over the last three seasons are pretty similar to the 4.20 ERA and 1.51 ratio that Worley put up in his worrisome 2012 season.

Coming up in the same division, Worley and Lannan each spent time in the Double-A Eastern League and Triple-A International League. Here’s what the two have done in each of those leagues:

Ages IP ERA Ratio H/9 HR/9 BB/9 SO/9
Lannan AA 22 and 25 76.7 3.76 1.37 9.4 0.6 2.9 5.6
Worley AA 21 and 22 266 4.43 1.36 9.4 0.9 2.9 6.2
Lannan AAA 22 and 27 186.7 3.76 1.37 9.4 0.8 3.0 5.1
Worley AAA 22 and 23 96 3.00 1.14 8.2 0.8 2.1 8.1

They have very similar numbers at Double-A with Lannan posting a better ERA. Lannan has thrown more than twice as many innings in the Triple-A Eastern League, but Worley’s numbers are significantly better as he has allowed fewer hits and walks while striking out batters at a higher rate.

The biggest question as we look towards 2013 and beyond is whether you think Worley’s enormous hit rate in 2012 was a fluke or not. He has close to no chance of being successful in the long run with opponents hitting .296 against him. He was also victimized by one of the highest rates of BABIP of all pitchers in baseball.

Todd Zolecki suggests that trading for a player like Vernon Wells or Alfonso Soriano might make sense for the Phillies if they don’t sign Cody Ross here.

Baseball America’s Top Ten Prospects for the Phillies was released with 21-year-old lefty Jesse Biddle at the top of the list.