Complex sentence: However, they failed to improve upon their record, becoming the second team to complete an 0--16, they became the first franchise in NFL history to have multiple seasons with 15 losses and the first to start consecutive seasons with at least 14 losses.
Split into simpler sentences: However, they failed to improve upon their record, losing their first 15 games for the first time in franchise history. In starting 0--15, they became the first franchise in NFL history to have multiple seasons with 15 losses and the first to start consecutive seasons with at least 14 losses.