while hes not considered "rookie" by MLB standards, he still hasnt endured a full 162 season yet in his short career.
It just seemed like you were basing your prediction on the above statement, which is incorrect. Given routine days off, most major leaguers play between 150-155 games in a full 162-game season. Howard has basically accomplished that feat in both of his last 2 seasons.
The article says he's tired and needs to rest, but most players are somewhat tired at the break. So relative to other players, I don't think he's an above-average candidate to slow down this season. I mean he hit 10 homers in September last year and we're entering the dog days of summer, so balls are going to be flying out of Citizens Bank Park.