PS3 was close to 4.5mil at the end of 2009 and it sold close to 1.8 mil in 2009. Even if it has a decline of 15%, it would still make 6 mil PS3 in Japan by Jan 2011. That's certainly achievable.
On the other hand, it is highly unlikely for PS3 to have 3 new million sellers.
GT5 has a good chance.
FF 13 Versus would do it if it's released.
FF14 is not likely since it's a MMO.
Yakuza 4 is also unlikely since 3 was at 500K and I don't think the series suddenly gained popularity to double its sale.
MikeB predicts that the PS3 will sell about 140 million units by the end of 2016 and triple the amount of 360s in the long run.