Complex sentence: At the close of the season, he received an offer to join Arsenal, but while his team-mates Cesc Fàbregas and Gerard Piqué soon left for England, he remained in Barcelona, where he began a rapid progression through the ranks.
Split into simpler sentences: At the close of the season, he received an offer to join Arsenal. While his teammates Cesc Fàbregas and Gerard Piqué soon left for England, he remained in Barcelona, where he began a rapid progression through the ranks.