Red Bull chose Perez and not Sainz: a mistake by Horner in hindsight?

Hindsight is a wonderful thing, as it turned out to be a wrong move by Red Bull Racing to extend Sergio Perez’s contract so early in the season. The team could have chosen to sign Carlos Sainz at the time; an experienced race-winner, trained by Red Bull, and someone who was rated higher than Perez by friend and foe alike. With Perez now gone, it seems a missed opportunity for Red Bull that Sainz was not committed.