Pulis is confident the 21-year-old is now ready for his baptism in English football and plans to start Arismendi in the third-round tie at home to Championship.
"Diego has settled in smashing for a young man who has moved so far from his homeland," said Pulis.
"He's very, very enthusiastic and keen and we are looking forward to seeing him play. He's done very well in two reserve games and he will definitely start against Blackpool.
"Diego is strong and good on the ball. He's looked after himself with no problems in training and we might just have found a very good player."