Arellanes was signed as an undrafted free agent by the Seattle Seahawks following the 1997 NFL Draft. After spending training camp with the team, he was released during the preseason on August 16. Later that year, he was signed to the Seahawks' practice squad. Following the 1997 season, Arellanes was allocated to the Rhein Fire of NFL Europe, where he was the back-up to Mike Quinn. Rhein finished the regular season in second place with a record of 7–3 and qualified for the championship game, World Bowl '98. Due to an injury to Quinn, Arellanes started the game and led the Rhein Fire to a 34–10 victory over the Frankfurt Galaxy, the first championship in team history. He completed 12 of 18 passes for 263 yards with three touchdowns and no interceptions, a performance which earned him Most Valuable Player honors.