The German was forced to retire from the season's first official practice session because of an electrical fault and could only manage the fourth fastest time in the second session.
His best effort of one minute 26.081 seconds was almost two seconds outside the lap record he set at Albert Park last year, and seven-tenths of a second behind McLaren test driver Pedro de la Rosa.
Although Friday's practice session does not count towards qualifying and this year's times were generally slower because of new regulations, Schumacher's performance may be the first sign that Ferrari will not have everything their way this year.
The Italian manufacturer won 15 of the 18 races last year with Schumacher taking the chequered flag a record 13 times on the way to an unprecedented seventh world title.
Schumacher's domination over his rivals was evident from the first practice session of last season and it was no surprise to see him qualify on pole position then go on and win in Melbourne for the fourth time in five years.
STILL SATISFIED
The German is less confident about his chances of winning in Australia this year after arriving with last year's car and troubles with Ferrari's winter testing but still declared himself satisfied with Friday's performance.
"It's always a nice moment to be back on track for the start of a new season," he said.
"I am quite happy with the first day. We nearly completed our full programme although I had a small electrical problem in the morning which meant I had to pit earlier than expected.
"It was fixed very quickly so we did not lose much time."
Schumacher's Ferrari team mate Rubens Barrichello was also slightly off the pace on Friday, clocking the 12th fastest time in the opening practice session before improving three places to ninth in the second run.
The Brazilian had a slight mishap when he slid of course in the second session but there was no damage and he was also upbeat about his prospects later in the weekend.
"I am happy with the situation although it is very difficult to understand everyone's true pace," he said.
"I had a slight problem with the balance of the car, a bit of traffic and I also went off track. I expect to be looking better tomorrow."
