I'll get to the title of this piece later. But first, what would you think about the following two players batting leadoff for your team:
Obviously, everyone would choose Player A over Player B. Player B makes an out almost 73% of his plate appearances and has no power. Player A, on the other hand, rivals Rickey Henderson's 1990 MVP season (.325/.439/.577).
What if, though, you were like the Phillies over the past two years and had both?
Yes, both Player A and Player B are Jimmy Rollins in the last two seasons for the Phils.
Clearly, though, these two lines aren't Rollins' individual seasons. Rather, I aggregated the notoriously streaky Rollins' good and bad streaks over the past two years to get to these lines. Aggregating the streaks resulted in pretty comparable playing time, as the good Rollins had 695 at bats over the past two years whereas the bad Rollins had 671. The streaks were a minimum of 40 at bats (maximum of 264).
(The good streaks: in 2005, 5/12-6/18, 7/8-7/30, 9/4-10/1, and in 2006, 4/30-5/11, 6/4-8/15, 9/19-10/2. The bad streaks: in 2005, 4/4-5/11, 6/19-7/7, 7/31-9/3, and in 2006, 4/3-4/29, 5/12-6/3, 8/16-9/18.)
As you can see from the summary lines above, the Phils had two wildly different leadoff hitters over the past two years. When Rollins was good, he was incredible. He got on base at a great clip, hit for power, drove in runs, scored runs, and stole bases. However, when Rollins was bad, he was terrible. Here's a fuller comparison of the two very different players:
Other than the strikeouts being about the same, the differences between the two are huge. The good Rollins dominated offensively; the bad Rollins was a wasted spot in the batting order.
How did the two different Jimmy Rollins affect the Phils?
With good Jimmy batting leadoff, the Phils were almost a .600 team; with bad Jimmy in that spot, the Phils were 9 games under .500.
And that brings us to Henry Wadsworth Longfellow:
There was a little girl,
Who had a little curl,
Right in the middle of her forehead.
When she was good,
She was very good indeed,
But when she was bad she was horrid.