Simplify the following text for a Grade 8 native English-speaking person.
Original: This guideline was later amended to 90 at bats , 45 innings pitched , or 45 days on a Major League roster before September 1 of the previous year .
Simplified: This guideline was later changed to 90 at bats , 45 innings pitched , or 45 days on a Major League roster before September 1 of the last year .