Let’s have a fun little thought experiment. What if July-to-present Jimmy Rollins had existed between April and the end of June? As we’re all aware of, Jimmy had a terrible first half, putting up a .572 OPS in 325 plate appearances. Since then, he’s hit for an .813 OPS in 372 PA.
The only tools needed for our experiment are:
I went ahead and plugged in all of the numbers — the Phillies’ batting order and their respective OBP and SLG. Then I selected the 1959-2004 model and clicked submit. This is easy!
The current Phillies lineup — including Rollins’ current level of production — comes out to 5.017 runs per game with the most optimal at 5.156.
For the second test, I simply replaced Rollins’ current OBP and SLG with that of his second half, .323/.490.
That lineup comes out to 5.183 runs per game with the most optimal lineup at 5.298. So, we can say that first-half Jimmy cost the Phillies .166 runs per game, or 13 runs over 81 games, a bit more than one win.
Should you have any questions about how the calculations work, click on the lineup analysis tool link above (or here) and click on the linked names after “Based on work by”. Cyril Morong’s article at Beyond the Box Score in particular is a great read.
Just for fun, I wanted to see how much better Carlos Ruiz has been than Paul Bako offensively. As above, the current Phillies line-up will score 5.017 runs per game. Replacing Ruiz with Bako brings them to 4.849 runs per game, a difference of .168, nearly the same difference between Good Jimmy and Bad Jimmy! Of course, it’s advantageous to rest a catcher so the total difference between the two catchers isn’t as large as the lineup analysis tool indicates. But it’s a fun thought experiment.