Speroni suffered a nasty throat injury against Ipswich earlier this season and Jones felt his confidence dipped as a result, but he was back in top form as the Eagles saw off Derby 1-0 last Saturday.
"The doctors were seriously worried about about him when he went into hospital that evening. When you damage your larynx like he did there is always immediate concern," said Jones. "What I am certain about is that it affected Julian's confidence but Saturday's performance was a sign that he has put that behind him now.
"The thing about Julian is that he has got this thing in his head about playing for Argentina in the World Cup.
"Argentina, as we know, are struggling, not more than in goal and when we played Manchester City and Newcastle, Julian never left (Carlos) Tevez or (Fabricio) Coloccini alone and I am sure he was ramming his name down their throats to speak to Diego Maradona on his behalf.
"But the thing against him is that he is at a Championship club. I am certain if he was in the Premier League he would be in the Argentina squad now."