How to defeat mental walls

Question
Dear Expert Willie Ansley,

My name is Emanuele, I am 21 year old and after almost 2 years without playing baseball due to an injury I started to play baseball in november again.
Now I am playing in a Junior College in Florida, the coach accepted me in his team but he didn't put me in the roster because the lack of training. I am just training to be back ready again.
I played in the Dominican Rep. to get some possibilities with a minor league contract, in fact I am a half Dominican and a Half Italian.
I remember before my injury at the knee that I was a great player, (yes I was!), but it is always the same problem at the time of try-outs or anybody else that wasn't a talent scout watching me playing my skills disappear like a ghost. I always get tense in everything, I also told this this to my currently head coach but I still don't know what to do.
Im writing this to you because I saw that Baseball is 90% mental, and I agree this opinion with you.
I only can tell you when I am quite and relaxed ther's no pitcher that can throw me that ball. And the coach accepted me because he saw on me skills that he really like.
Now I am training hard every day also after practice to get back and play summer league and reach my goal soon as possible or rather get signed by a minor league team and reach the major league, but the mind is against me and it doesn't let me do what I can do.

Answer
Emananuele, its sounds like when its time to perform you are putting to much pressure on yourself.If you allow all the pressure to come out then you will stiffen up and look bad. What I would suggest is to stop thinking about a minor league contract and think more about going out having fun.Its not a life or death situation.Relax and let your skills show.