The 38-year-old is more than capable of extending his glorious career even longer, although Paul Scholes seems unlikely to play beyond 2013.
Giggs, currently preparing to captain Great Britain in the Olympic warm-up fixture with Brazil in Middlesbrough, is targeting a 13th Barclays Premier League winner's medal next term. Scholes has 10 championships under his belt and performed well last season after coming out of retirement in January.
"If we can get a good season out of Paul, he will be satisfied with himself," said Sir Alex. "On the other hand, Ryan can play for another year after this."
The boss has also set Rio Ferdinand, currently 33, a target of being able to play for another few years at the top level.
When asked if the centre-back will ever represent England again after being excluded from the Euro 2012 squad, Sir Alex replied: "I don't think so. It's not on his agenda either. He wants to ensure he's fit for us.
"As a centre-back, if you stay fit and look after yourself, you should be playing until you are 37."