Adjusting for park does take the Manfred Missile into account.
If the OPS in, say, Fenway for all hitters was .750, and this year it’s .850, you get a higher league average OPS aka an OPS+ of 0.
For example, last year Bogaerts had an OPS+ of 134 with an OPS of .883. This year Betts has an OPS+ of 135 with an OPS of .906. In 2009, or the year 6 BM (Before Manfred), Jason Bay had an OPS+ of 134 with an OPS of .921. The baseline moves...