DiPietro, who this summer enjoyed his first healthy offseason in years, took a puck off the face mask during practice Wednesday. He underwent baseline neurological testing Thursday and did not dress in the team's 5-1 win over Tampa.
The 30-year-old goalie, who is signed through 2021, has been plagued by injuries throughout his career. He missed six weeks last season with a concussion and facial fractures suffered in a fight with Penguins goaltender Brent Johnson.
Given DiPietro's stunning injury history -- which includes multiple hip and knee surgeries -- the Islanders wisely elected to keep three goaltenders on their opening-night 23-man roster.
The Islanders claimed the former Vezina Trophy finalist off waivers from Detroit last January and subsequently suspended him when he refused to report. After the Islanders tolled his contract to retain his rights for this season, Nabokov decided to attend training camp in September.
He found himself third on the depth chart out of camp -- he was scratched the first two games -- but has by far the most NHL game experience of all the goalies.
When asked about Nabokov before Thursday's game, Islanders coach Jack Capuano said:
"He's an experienced guy. He's gonna get his chance real soon and I'm sure he'll make the most of it."
Katie Strang covers the NHL for ESPNNewYork.com.