Firstly, I would remove the link as you are not allowed to link to a player on the transfer list.
Secondly, great defence for a 19 year old but pity the other skills aren't very good.
Thirdly, assuming the player started with respectable OD that means he has had 9 pops in outside defence.
Chances are that he was 1 position trained for OD every week and no other training has been applied.
There has been 20 training weeks so far. So that means 9 pops in OD in 20 weeks.
Considering that he was 18/19 years old and because he is so short I think it explains why he average 1 pop every 2 to 2.5 weeks.
I think you could do this with a level 4 trainer if the OD of the player started at respectable with a high sublevel.
I am also surprised his salary isn't higher, although the salary calculator estimates his current salary (with the high defence) to be around 8k, so I am guessing that the reason his salary is so low is because all of his other skills are quite low.