The shaggy-haired Barcelona defender has been a fixture in the centre of the Spanish defence during their recent successes at Euro 2008 and in the 2010 World Cup, but a knee injury has kept him on the sidelines for the last eight months.
The 33-year-old last appeared for Spain in the 4-0 friendly defeat against Portugal 11 months ago, but is likely to earn his 95th cap in the Euro 2012 qualifiers either against the Czech Republic in Prague on Friday or in Alicante against Scotland next Tuesday.
"We are pleased and very happy for him, because we know he has suffered a lot, and mainly in silence," Casillas told a news conference in Prague.
"He is a reference for everyone who comes into the national team for his professionalism."
Puyol said he had considered retiring in a recent television interview but has slowly been working his way back to fitness and has been used sparingly by club coach Pep Guardiola at the start of the current campaign.
"We are pleased he can return to play with us again, and that he is back in the squad," Del Bosque said.
"There is no reason for him to have lost any of his understanding with [Barca and Spain team-mate] Gerard Pique. Ideally they will return to play together for us and for their club.
"There are still many months to go until Euro 2102 and we will take it step by step."
Puyol won his first cap against Netherlands in 2000, and has scored three goals, including the thundering header against Germany which fired Spain into the World Cup finals last year.
Spain have already qualified from Group I to defend their European title in Poland and Ukraine, but play the two sides vying for second spot over the next few days.
"We know we have to be good professionals and sportsmen to defend our reputation and because we will be the arbiters of where the two teams finish in the group," Del Bosque added.
"Let there be no doubt. The worst thing a team could do would be to play without a competitive spirit."
Spain have won their last 20 qualifying games for international tournaments since a 1-1 draw with Iceland in September 2007.
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