Pretty much everybody around here seems to want to ditch Livan Hernandez in favor of Francisco Liriano, the Second Coming of Johan "Should've Won 3 Cy Young Awards By Now" Santana. So, much like I did with the question of batting Gomez 9th, I decided to grab some perspective by calculating the added run value of simply releasing Hernandez and calling up Liriano to take his place.

My question is this: How many more runs will the Twins prevent the opposition from scoring if Liriano gets Livan's remaining 11 starts?

Creating projections

First we need to gauge each player's true talent level. This is easy to do for Hernandez; I just plug his stats and birth date into The Hardball Times' in-season Marcel projection spreadsheet. This yields that Livan should be good for a 4.74 (fielding independent) ERA over the remainder of the season, meaning that his aggregate ERA for the 2008 season would end up at 5.11.

It's a bit more difficult for Liriano, since I want to base my analysis on his excellent work in Rochester this year as well. It's not right to just plug in his minor league totals, since the level of competition obviously doesn't match what he would face in MLB, and furthermore, Marcel bases its projections on major league averages.

Thus, I went to Baseball Prospectus to look up Liriano's minor leagues stats translated to a major league context. This transforms the Franchise's 3.10 International League DERA (defense independent ERA) into a 4.09 major league DERA. I typed the relevant translated statistics into the Marcel pitcher projection spreadsheet as a separate 2008 row, and voilà: We get a 3.63 true talent ERA for Liriano.

The big (?) difference

Having done the above, it's easy to see how many runs Liriano would save more than Livan. Over 9 innings, Liriano is projected to allow 1.11 runs less than Hernandez, which is 0.123 runs per IP. The Twins have 55 games left to play in the 2008 season, so that's probably around 11 remaining starts per spot in the starting rotation. Hence, if the Twins swapped Francisco and Livan right now, it would probably affect approximately 66 remaining IP (6 innings a start seems about right to me).

Multiplication shows that Liriano is then worth 8.14 runs more than Livan from this point of the season and out.

Conclusion

As in the case with Gomez, the added run value is quite a bit smaller than I expected. 8 runs is equivalent to a little less than one win in the standings. Now, one might argue that Liriano's projections are a bit conservative, since he has pitched way better as of late, and we should probably assign more weight to these stats than to the stats from the beginning of the season. However, I don't think this would change the result much.

Still, the Twins need to do this move. If they can trade Hernandez before the deadline, they would only gain from that on the major league level and maybe receive some fringe prospect as icing on the cake. It would also help Liriano's development tremendeously, as he is obviously getting tired of fanning AAA batters.

Whatever "veteran presence" Hernandez provides, it can't possibly outweigh the positives of having Francisco take his spot in the rotation.

That's my two cents - what are your thoughts?