Yankees try an old trick by trading for Headley

Our own Ken Rosenthal is confirming this morning that Padres 3B Chase Headley is headed to the New York Yankees for Yangervis Solarte and Rafael DePaula along with some cash in the deal. I don't get it.
Headley was really good two years ago when he hit 31 home runs with an NL-leading 115 RBI to go along with a career high .875 OPS. That was two years ago. This year Headley is slashing .229/.296/.355. A combination of Yankees third basemen this year are slashing .260/.330/.393.
Headley is a major upgrade defensively as he rates near the top of all 3B in baseball. The Yankees this year have gotten at best league average defense at 3B. Headley's a free agent after the season, so this looks like a short-term rental.
The only justification for this deal is that the Yankees are trying to get better defensively at 3B. They'll be getting the same or worse offensive production that have been recieving all year. The Yankees making trades for defensive upgrades? When did they get so boring?
Or maybe they're trying to repeat an old trick like when they acquired Scott Brosius after a season in which he hit .203 in 1997. The next few years went pretty well for them.