I haven't been tracking salaries, but I believe Erstad is still the most expensive position player taken thus far. 1965 Willie Mays was close at $9.5M. At a glance, I don't see any other hitters in the same zip code.
Plenty of expensive pitchers, though. Greinke, Perry, Luque, Arrieta, McNally, Cooper, Kershaw, Lemon, and Spahn are all over $10M...
Only two owners have more than one player in the $10M club: Ribbentrop (Perry, Luque, Lemon) and Ronthegenius (Arrieta and Spahn).