One thing that will work against anyone breaking Blyleven's record is the fact that neither the players or the baseballs will be as juiced this year. I really think that you will see a significant drop from the over 5400 home runs hit last year despite the watered down pitching at the Major League level. You are already starting to see the 50 home run season become a thing of the past with no one reaching that total since 2001.

Although if Dunn can learn to make contact a little more frequently if has a chance to easily surpass that total.

I know it's quibbling, but A-Rod hit 57 in 2002.  I would disagree that home runs will be down this year.  Players may not be as juiced, but you can bet that if MLB can do anything to make their players look better in the face of steroids they will.  I imagine they will find some way to massage the home run numbers up this season, in order to try to legitimize the past few seasons.  If they can say, "Look, our players are still hitting home runs even with a more publicized steroid policy," it would be less of a black eye on the league.

I don't think that Milton will give up any more home runs than he did last season since Citizen's Park was more of a launching pad than GABP (it increased home runs by 13% compared to GABP's 5% increase).  That being said, he could still give up 40 long balls, and that isn't good in any park.