He was awarded $4.3 million on Friday by Steven Wolf, Robert Herzog and Gary Kendellen rather than his $5.75 million request.
The 29-year-old Donaldson hit .255 with 29 home runs and 98 RBIs in 158 games last season for Oakland and was traded to Toronto in December for third baseman Brett Lawrie, left-hander Sean Nolin, right-hander Kendall Graveman and minor league shortstop Franklin Barreto.
In four seasons in the majors with the A's, Donaldson has a .268 average with 63 homers and 228 RBIs.
He earned the $500,000 minimum last year and was eligible for arbitration for the first time.
Teams lead players 5-3, with the remaining seven cases scheduled for next week. The eight hearings are the most since clubs went 5-3 in 2010. There have not been more since teams were 8-6 in 2001.