Defining 1-2-3-4-5 Starters
It is very common when doing prospect analysis to refer to a pitcher as a "potential Number One starter" or "perhaps a Number Five starter." What exactly does that mean? Every team has five (or four, or six) starting pitchers in the rotation at any one time, but not every team has a "Number One starter" in the sense that scouts mean. Let's explore this.
As a starting point, I'm going to take the ‘overview' of what scouts look for when they use these terms, as defined on page eight of the 2012 Baseball America Prospect Handbook, then flesh those out with my own thoughts and some examples.
NUMBER ONE STARTER:
**Two plus pitches
**Average third pitch
John's Commentary: The BA list should be seen as a rough guide and a "minimum qualification". The best Number Ones have more qualities than the ones on the BA list. For me, a Number One starter is a guy who anchors your rotation, will be in line for the All-Star game most seasons, and is on the pre-season candidate list for the Cy Young Award. The exact style can vary between pitchers, but the results have to be there.
Current examples of a Number One starter include Justin Verlander, Felix Hernandez, Clayton Kershaw, and Stephen Strasburg. Roy Halladay in his prime. Greg Maddux, Pedro Martinez, and Roger Clemens were all Number One starters, although their styles differed. There aren't a lot of these guys active at any one time, certainly not enough for every team to have one. These are the guys who end up in the Hall of Fame if they last long enough.
NUMBER TWO STARTER
**Two plus pitches
**Average third pitch
John's Commentary: A Number Two starter is similar to a Number One, but not quite as good for a variety of reasons, perhaps not as consistent or durable as a true One.
The dividing line between the two categories is blurry, and some Number Two starters will have Number One-quality seasons at times, although they may not sustain the performance year after year. These guys can certainly anchor your rotation. Number Twos can be considered aces for most teams, and will be on the short list for the All Star Game many seasons. A team with a Number Two in the top spot of the rotation can certainly win the World Series.
Current examples: for me, Zack Greinke is a guy who exists right on the borderline between a very strong Number Two and a Number One, as does Gio Gonzalez. Johnny Cueto has pitched like a Number One for the last year and a half but hasn't proven to have that kind of long-term durability yet so would rank as a strong two for me. Matt Cain and Madison Bumgarner.
You can build your staff around a Number Two starter if you don't have a full-fledged One, and most teams don't. Calling someone a Number Two is a compliment.
NUMBER THREE STARTER
**One plus pitch
**Two average pitches
John's Commentary: These are the guys that soak up innings for you, usually with average to slightly above-average performance, but who don't meet the standards to be a One/Two. For weaker teams, a Number Three may take the first slot in the rotation and be the de-facto ace. There is usually a fairly clear dividing line between a Number Three and Number One/Two. It's like pornography; you know it when you see it.
This is healthy Mike Pelfrey, Jake Westbrook, Joe Blanton. Jim Lonborg. Brad Radke was a Number Three starter who became the default Number One for the Minnesota Twins in the late 1990s. Jon Lieber. Kevin Tapani. Jon Garland. Jason Hammel. Phil Hughes.
NUMBER FOUR/FIVE STARTER
**Command of two major league pitches
**Consistent breaking ball
John's Commentary: A guy to soak up innings, but who isn't as good or consistent or durable as a solid Three. The styles here can vary wildly. Some of these guys are control artists who lack plus stuff, others have plenty of stuff but don't command it well.
Examples are legion. Old Barry Zito. Ivan Nova. Blake Beavan. Luke Hochevar.
Something to consider: fans are often disappointed when a prospect is referred to as a "Future Number Three starter," but that's actually a huge complement. Even calling someone a Future 4/5 isn't a bad thing: there aren't enough 1/2/3 guys to fill every major league rotation spot, and even if a guy is just going to provide 170 so-so innings, that's still valuable.
Also note that someone can be a Number One or Two starter in his prime years, but fade into the lower category as they age and begin to lose their skills.