re: player form, ah! Well, that happens in baseball and it doesn't. First of all, as a batter, there's the old saying that you're a future hall of famer if you only fail 7 out of every 10 times (a .300 batting average is pretty good). But then again, a player could go 0 for 4 or 5 in a game and some might still say, well, he hit the ball hard, he just got unlucky by hitting them right at the fielders. You could do that for a few games in a row and still not many might be on your case. Some fans of course would be screaming for the manager to play someone else. Eventually, no matter how hard a player may be hitting the ball, a manager will probably change guys up if they're just not hitting over several games.
They might just want to "shake things up" too, as it is often the case (or at least it may seem that way) that when a manager moves people in the lineup or replaces 1 or 2 guys, the offense will come alive. Some managers will also "platoon" guys at a position which means 2 or more guys might split time starting at a certain position. All that said, it's really rather variable. Some people have the philosophy that you stick with your guys as much as possible, whereas some managers really do like to make a lot of moves. I'm the former type, but if you're the latter, that's perfectly legit too.
Pitchers, however, are a bit of a different story. They, of course, need to succeed at a much higher rate than batters (>7 times out of 10) and if a pitcher is at all looking like he's struggling over more than 2 batters, he'll probably be pulled for a reliever. That, of course, depends on a number of factors: how early in the game is it, how big of a lead do you have if you have one at all, how rested is your bullpen (you'll often need more than 1 reliever in a game, obviously more the earlier it is, and maybe even more than you think as the game might go to extra innings), how good are your available relievers, etc, but managers do typically have a much faster hook on pitchers than batters. It's not just in one game either. If a pitcher has 2 or 3 really bad outings in a row, if the team has "options" on him, there's a good chance they'll send him down to the minors and bring up a guy from down there who's hot.
Lastly, from year to year, how good any one reliever will be tends to be a lot more variable than any one starter. Starters, you see, tend to have 3 or more kinds of pitches and so they have more ways to get a guy out so if one way isn't working they usually have other ways to use. Relievers, however, if their only 1 or 2 pitches just aren't working for them, they're in a lot of trouble as they don't have anything else to fall back on while they figure out what's wrong with them. It could be an overall problem, of course, too, but that's my theory at least on why relievers, in general, are less reliable than starters.
I'm glad you found it and like it, the game and the sport. The more fans the better!
