18 year olds go for so cheap on the transfer line, you can find 4,000 + salary guards with allstar or more potential for less then 100,000. You should definetly focus your training on him and I would start with training outside defense until it is strong/proficient and then train the rest so then he looks something like this.
Jump Shot: strong Jump Range: average
Outside Def.: proficient Handling: average
Driving: respectable Passing: strong
Inside Shot: average Inside Def.: atrocious
Rebounding: respectable Shot Blocking: mediocre
Stamina: atrocious Free Throw: average