Messi has been locked in talks with Barcelona for a number of months with his current deal up at the end of next season.
He has been linked with a mega-money move away this summer, with Manchester City one of the clubs rumoured to be on his radar.
Spanish football expert Balague expects the 29-year-old to commit his long-term future to Barca but doesn't know when.
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Guillem Balague says Lionel Messi's contract talks with Barcelona are going well
His dad has met a Barcelona representative last Friday
Guillem Balague on Lionel Messi
"His dad has met a Barcelona representative last Friday," he said on Sky Sports.
"They both told each other: don't discuss this with anybody.
"They're both saying 'I won't' which means we don't know how well it's going.
Guillem Balague says Lionel Messi's dad met with a Barcelona representative last Friday
"The message coming from the club and from Messi's side is going well.
"When will it be signed? We don't know yet.
"It's going well."