Donald was over eight seconds inside the official lap record on Thursday
Saturday's scheduled Superbike race at the Isle of Man TT has been called off because of heavy rain.
The Superbike race and Sidecar TT would have opened the meeting but they will now take place on Monday.
Monday's planned Superstock and Supersport races will now be held on Tuesday with the second Supersport and Sidecar races on Wednesday.
Meanwhile, Cameron Donald suffered a suspected dislocated shoulder after crashing in Friday's final practice.
The Australian, who set an unofficial lap record on Thursday, now looks certain to miss Monday's Superbike opener after coming off at Keppel Gate.
The TAS Suzuki rider became the first man to lap the island course at over 131 mph on Thursday.
On Friday Steve Plater set the fastest Superstock time of 126.93mph.
Plater's time saw him just edge out Ian Hutchinson, who recorded a speed of 126.84 mph.
Plater, riding for HM Plant Honda, set his fastest Superbike time of the week in Friday's session (128.93 mph) but it didn't improve on his existing sixth place in the practice standings.
William Dunlop improved to seventh in the Supersport qualifying after posting a lap of 123.34 mph while his brother Michael and Ryan Farquhar both improved their superbike marks in Friday's session.
Michael Dunlop posted a 125.74 mph superbike lap with Farquhar improving to 126.73 mph but both were still outside the top six and well adrift of Donald's remarkable circuit (131.45 mph) on Thursday.
Race organisers reported that Donald was "conscious and talking" after his crash on Friday and it was later revealed that he has suffered a suspected dislocated shoulder.
2009 TT Best Times
1. Cameron Donald (Suzuki) 131.45 mph
2. John McGuinness (Honda) 130.17
3. Bruce Anstey (Suzuki) 130.12
4. Guy Martin (Honda) 129.16
5. Ian Hutchinson (Honda) 129.03
6. Steve Plater (Honda) 128.93
1. Steve Plater (Honda) 126.93 mph
2. Ian Hutchinson (Honda) 126.84
3. Keith Amor (Honda) 126.76
4. Cameron Donald (Suzuki) 126.43
5. Guy Martin (Honda) 126.05
6. Gary Johnson (Honda) 124.94
1. Michael Dunlop (Yamaha) 126.29 mph
2. Ian Hutchinson (Honda) 125.18
3. Keith Amor (Honda) 124.22
4. Bruce Anstey (Suzuki) 123.87
5. John McGuinness (Honda) 123.86
6. Steve Plater (Honda) 123.39