You can definitely train this draftee and it is also a good idea to start with outside skills.
However, it also depends on what you want to train with regards to your U21 PG.
The center draftee needs mainly PS and JS to get more rounded. Is that what you want to train for your PG as well?
Some OD, Driving and Handling might also not hurt and would push him more towards PF.
I would even say you should consider training outside skills for two full seasons and then move to the inside skills.