Hey Jake,
I like to have some idea about how long a leash a manager is going to give his starter.
Factors include bullpen availability, the number of pitches the starter threw in his previous start, any arm concerns, etc.
I don't so much trust history vs. one team - although in certain cases a pitcher truly does dominate one team - but lineups change constantly, and I don't believe the numbers truly apply from one lineup to another.
The L3 game is a good starting point, because it shows who has confidence. But confidence seems to build sometimes through the efforts of others, too. In other words, a struggling pitcher can catch the momentum of his teammates in a hot streak, so don't necessarily bet against a recent struggler if his team has won several in a row. (I don't know how to explain that, but it's true.)
Check the local newspapers daily. Make notes of what managers, opponents, teammates say of a pitcher's arm. Do NOT take the pitcher's own words for honest!! They have to try to remain confident, and they NEVER admit if they're hurting.
Always check the "Today's Game" box, where a reporter gives a brief synopsis of who's starting, how he's done, and hopefully, what to expect. Sometimes they just report the numbers, but baseball handicapping has to involve more than numbers.
You might discover than a manager just wants six innings from his rag arm, or that the bullpen is worn down and he is needed to go as far as possible. You might find that a pitcher has been battling blisters, and five innings is often his max, even if he's going well. You might find that the bullpen's weary.
* - One warning. Don't always bet against a worn-out bullpen. This day and age, a manager will definitely bring up a guy from Triple-A on a moment's notice before he will allow his BP to be totally spent. If this is part of your capping a particular game, check the wires around 5 p.m. local time before a game. By then, a club will have announced whether it has called up a player.
True handicapping a pitcher demands more than looking at his numbers - even though many of us love baseball because of the numbers. But if you don't know the facts behind them, the details (good stuff in a loss that impressed the catcher, for example), you don't know the whole story.
One tip for exhibition season: Pitchers start in clusters. Joe So-so for three innings, John Slapdick for three innings, etc. Try to find a game in which at least two who are COMPETING for a starting slot are going. Those are the guys truly at full strength during spring.
Example: Texas won on Monday with strong competition between Mickey Callaway and R.A. Dickey -- two average pitchers who are motivated in spring. They want to win a spot in the rotation. (If it can work for the Rangers, it can work for any team.)
Just don't try this system during the regular season!
Good luck,
Mook