Outgoing Ferrari president Luca Di Montezemolo confirmed, as expected, Spaniard Alonso will leave the Italian Formula One team at the end of the season.
Alonso has been strongly linked with a move to McLaren, where he spent one season in 2007, but is also reportedly considering taking a year out.
Former McLaren driver Blundell can only envisage the two-time world champion making a return to the Woking-based team if he opts against taking a sabbatical.
"Where is there left for Alonso to go? Pretty much only McLaren for something that's got the platform that he needs." he told Perform.
"That relationship has already been and gone once, so we'll have to see whether certain people have mellowed and whether that partnership can get back together again.
"Ferrari isn't at the level of performance that it should be. That's quite frustrating for those guys when they've got that ability and those credentials. They want more.
"But there's a lot more that goes on than just what you see on track. Sometimes some of those inputs have an effect."
McLaren's progress next season will be keenly watched throughout the sport as they trial Honda's power unit in their return to F1.