According to Swedish paper Aftonbladet, there's a reason for the absence of Penguins prospect defenseman Lukas Bengtsson . Here's a (sometimes hilarious) rough online translation
Lukas Bengtsson joined Frölunda Mora made his success. Last season the defenseman (had) big (Season), accounting for ten goals, twelve assists and took Frolunda all the way to the SM-gold. Then came the reward: a contract with the Stanley Cup champion Pittsburgh Penguins. But now he has got a heavy vengeance.
Bengtsson has suffered from Lyme disease and had large portions of the preseason destroyed by the disease. "I trained at home in Sweden last summer, but felt constantly tired.