Complex sentence: Both were the starters as the "Colchoneros" returned to the UEFA Champions League in 2008--09 after a 12-year absence, with Perea appearing in 30 league matches; after the season kicked off, he received his Spanish passport.
Split into simpler sentences: Both were the starters as the "Colchoneros" returned to the UEFA Champions League after a 12-year absence, with Perea appearing in 30 league matches. After the season kicked off, he received his Spanish passport.