Lombardi told The Times he visited Stoll in the hospital and that the veteran center is expected to be released at some point Wednesday.
"Everything is OK. They've run some tests and they still had another one to run," Lombardi told The Times. "The bottom line is that he's fine. Now the issue is what caused it."
Stoll suffered a concussion in Game 1 of the Western Conference semifinals, but returned for the first game of the conference finals.
Lombardi chose not to draw a connection between Stoll's concussion history and his seizure, telling The Times, "There are a myriad of things that can cause them."
Stoll, 31, played in all 48 of the Kings' regular-season games and tallied seven goals and 11 assists. He also added one assist in 12 playoff games this year.
Stoll joined the franchise in 2008 after five seasons with the Edmonton Oilers.