I agree the Cards will stay close enough for the the Reds to feel them nipping at the heels. They'll probably stay within five games of the Reds all season and will certainly be in contention for the Wild Card spot.
However, I am not ready to count out the Pirates. I am not as confident that they are not going to show this year. I watched them fade late last season, but if they win a few games in the division, they could be up within six or seven games out, as well. The Brewers will most likely finish 4th in the division, but they won't go quietly.
The Cubs will finish last, but the Reds are going to have to play them tough and make sure they treat the Cubs like a first place team playing a last place team. If the Reds can win 75%-80% of their season games against the Cubs, and win about 60% of their season ames against the Brewers, they can afford the luxury of splitting season games with the Pirates and Cards. But if they give away games to the Cubs and Brewers, it's gonna be a LONG summer.