Nick Johnson

I am having a hard time deciding how I should value Nick Johnson when it comes to preparing for my fantasy baseball drafts. The most similar batter by age (according to baseball-reference.com) is Travis Lee. When Lee was in his forth season - he got to play full time (555 at bats) and he hit 20 HR with 90 RBI while hitting .258 with a .341 OBP. Johnson will probably have similar numbers (although potentially higher BA and OBP). On the other hand - what if Johnson blossoms the way many people have predicted for him (plus the park in Puerto Rico tends to give up lots of HR)? On the other other hand - there are at least 15 1st basemen who will put up better than 20 HR and 90 RBI. What to do...what to do...