Four games missed with an apparent rib cage injury seemed like an eternity to Scott Hartnell. “I hate missing games, it’s not fun,” the left wing, who is expected back in the lineup Saturday against the Islanders in Uniondale, N.Y., said. “It’s frustrating to watch.” The Flyers lost three of those games. Hartnell took full practice with projected linemates Brayden Schenn and Jakub Voracek on Friday. Coupled with the roster move of sending Tye McGinn back to the Phantoms, that means Hartnell will play. “I feel pretty good,” Hartnell said. “Since Monday, since I started skating with the guys, I felt stronger and stronger every day. I don’t think there’s any risk to make it any worse out there. Hopefully, I’ll be in the lineup.” He said nothing would hold him back either, though he’s still lacking in game conditioning. “It’s amazing,” Hartnell said. “You can do an hour cardio every day for a month. The first time you skate it feels like you haven’t skated in your life. If anyone can invent something to replicate skating stride in a cardio workout, they will probably become millionaires.