So, I took a look at all the Hall of Famers who went in as hitters, not pitchers, and I wanted to know who had the worst final seven years of their career going in. Since these guys went in for hitting, instead of using WAR, which includes defense, I am going to use offensive WAR (oWAR), since it contemplates only the offense part.
Here are the ten worst seven-year offensive swan songs by a hitter before going into the Hall:
Ray Schalk is the worst with a mere 1.7 oWAR for his entire final seven years, but he was definitely not known for his hitting, so really, no surprise.
Al Simmons did go in for his hitting, but it was definitely for his first eleven seasons, and oh, what a stretch that was. He'd had almost 2,200 hits already, 240 of which were home runs, but his batting average is what really stood out: after his eleventh season, he was standing at .354 lifetime. He was considered to have had a puncher's chance at Ty Cobb's lifetime mark.
But then, starting with his 14th season, he was getting old, and he started getting hurt a lot, and he limped through that final seven-year period with a .278/.328/.431 line across 1,600 PA, resulting in an oWAR of 3.0.
I bring this up because for the past six seasons, Miggy, in a little more than 2,400 plate appearances, has slashed .262/.329/.386, which results in an oWAR of -0.2. So, unless he has a Pujols-like renaissance next season, Miggy is certain to walk backwards into the Hall with the worst final seven years of any Hall of Fame hitter ever—worse even than non-hitter Ray Schalk.