At this hour, it appears Prince Fielder will be skipping over Lake Michigan from Milwaukee to play with the Tigers in Detroit, and that has to be a bit worrisome for the National League.
Earlier this post-season, Albert Pujols bolted from the Cardinals to the Los Angeles Angels. If the Fielder deal comes through, that will mean that the top two sluggers in the NL have jumped to the AL.
With free agency, there are no doubt a zillion reasons athletes consider when deciding to sign with a particular team. With Pujols and Fielder – both slugging first sackers – I have to think that the designated hitter position in the AL was a factor, and possibly a significant one.
Even if their legs give out, they’ll be able to keep coming to the plate in the AL longer than they would in the NL. An American League team can offer a slugger the DL and thus stretch that multi-million dollar contract a bit longer.
The Ball Caps Blog 
fielder to detroit took me totally by surprise,
but then again, that’s where his pops-cecil played
and apparently, prince hit em’ out of the old tiger stadium as a 13-year old.
but as for right now, as you mention, the national league loses its stwo major sluggers and is looking, well, more than ever like the national league.