Tomas Holmstrom is 40 years old. That's pretty up there in years to still be playing a professional sport, especially one like ice hockey. Holmstrom had a great career in the NHL, including winning 4 Stanley Cups. He has earned the right to retire graciously. He may be doing himself a favor and avoiding injury or looking to become a coach or adviser. Tomas "Homer" Holmstrom will be missed, but best of luck to him.
Professional athletes punish their bodies day in and day out, usually from a very young age. Although some pro athletes stay in the game until their bodies are broken and they have no time to develop other skills for new professional opportunities, the smarter athletes retire while they are still healthy and while they can still pursue a career as an on-air personality, coach, scout, or consultant.
We have no real idea as to why Tomas Holstrom retired from the NHL. Maybe he was getting up there in age, and wanted to make sure he didn't get badly injured. Maybe he was playing so well and had won so many Stanley cups that he felt there was no where else to go. No one but Holstrom really knows why he retired, and that is fine by me.
While Tomas Holmstrom was a fantastic player, he was getting old for the game. At 40 years old and having played for 15 seasons, he was definitely one of the older men in the NHL. He has had a very impressive career, but now it is time for him to move on and make some room for some younger players. He has a family to pay attention to and now they will get his full attention.