In all sports, players go through slumps and streaks. It's hard to explain one single thing that may cause these streaks and slumps, but the only thing you can do is keep working hard, don't cheat yourself and hopefully the sporting gods will take care of you and repay you for all the hard work you put in.
I can honestly say right now, I am going through a bit of a cold streak but it's not quite a slump. During Spring Training I threw 7 innings, 1 hit, 1 run, 1 walk and struck out 12. The one hit I gave up was a solo home run. So everything ran smoothly for me in Spring Training. I kept doing the same routine everyday, hoping I could keep repeating every performance. But in Extended Spring Training now, I have thrown 10 2/3 innings, 12 hits, 6 runs, 4 walks and struck out 16. I have done all my routines the same, but the results have been different. All I can do is work harder in my bullpen sessions, put in while I'm in the gym, and make things turn around in my favour.
There is a difference between a slump and a cold streak, a cold streak is usually a lack of production over a small period of time, such as a hitter going 0 for 12 over 3 or 4 games. when a player starts to buy into their cold streak, then this may turn into a slump. A slump is when a hitter hits .100 in a month. Slumping can cause a player to change their own workouts, and they start to press. This pressing can lead to behavior that sometimes borders on maniacal. A player in a slump can often be found asking anyone and everyone what they are doing wrong. Just recently I was speaking with another pitcher here asking how I could improve my curveball since mine has lost a bit of bite to it. There is one good thing about slumps, they are great teachers. No player can avoid a slump. Slumps allow a player to learn more about their own mechanics or just themselves so in the future they will know what to look or feel for when things aren’t feeling just quite right.
The behavior that accompanies a hot streak can be very similar to slump behavior because superstitions can start to pile up. When a guy gets hot or has a hitting streak going, or a pitcher has a scoreless innings streak, sometimes he begins to attribute his success to things that have nothing to do with it, like a pair of lucky socks or oddball routines, or wearing the same underwear. It can get pretty hilarious what people come up with as superstitions as you can see from my blog entry 'Superstitions and Habits'. I'm one person that is very guilty of following the same pre game routine if I had a successful outing with that routine.
While on a cold streak, it may look like the entire field is a big glove, but while on a hot streak, the ball may look like the size of a watermelon.