While Spain have become known for their mesmeric passing game, their success at the last two European Championships and the 2010 World Cup was also built on defensive solidity, epitomised by the never-say-die attitude of the talismanic Carles Puyol.
His last-ditch challenges and aerial strength at set-plays inspired his team mates and it was his header from a corner in their semi-final against Germany in South Africa that booked Spain a place in the World Cup final.
He was missing through injury for Euro 2012 but Ramos and Gerard Pique provided a dependable partnership in front of goalkeeper Iker Casillas who was in his prime and making saves that led him to be nicknamed 'Saint Iker' by fans.
Ramos has since taken on the leadership role from the retired Puyol and is undoubtedly one of the top centre-halves in the world. Pique's star has been on the wane, however, and there is not much competition for places behind him.
While Spain failed as a team at this year's World Cup where they went out in the group stage, Pique in particular was exposed for his lack of agility when strikers ran at him.
At club level this season he is no longer an ever present in the Barca side with new coach Luis Enrique appearing to prefer the combination of Jeremy Mathieu and Javier Mascherano.
Del Bosque admitted that it has become a problem position.
"There are a lot of foreigners in the league and it is true that we are lacking a bit in this position," Del Bosque said. conference.
"It is the same in the Under-21s that with so many players from abroad they have hindered the progression of our own."
With Ramos out with a calf strain, Bartra, who is behind Pique in the pecking order at Barca and has been given little playing time under Luis Enrique, has been drafted in.
For Spain's World Cup qualifiers against Slovakia on Thursday and Luxembourg on Sunday they are likely to have Pique and Napoli's Raul Albiol at centre-half with another option, Javi Martinez, also injured.
However, Ramos denied there was a lack of quality.
"There is no doubt that Pique has been playing for the national team for many years and has done well. He will always have chances," Ramos told reporters.
"We are not worried about any position (in the team). Recently we have had a lot of centre-halves called up so I think the position is well covered."
