Timonen, 39, has not played since being diagnosed with blood clots in his leg and lungs in August. He has Protein C deficiency, an illness that makes him susceptible to blood clots. Timonen's mother and two of his brothers also have the illness.
He skated by himself for about 40 minutes at the Flyers practice facility in Voorhees, N.J. Flyers general manager Ron Hextall looked on as Timonen worked in some stickhandling and shooting.
"It was kind of a weird feeling this morning," Timonen said in video posted on the Flyers website. "I was kind of nervous that I don't fall down right away. It was kind of weird, but I was so excited looking forward to this morning. I couldn't really sleep last night. It's not like you're riding a bike. It's different. I just realized skating is hard. This is kind of like a training camp for me, Day One. It's over, but it's going to get better day by day."