Ok, here we go.
Houston Texans WR Kevin Walter (hamstring) did not participate in practice Thursday, Sept. 10.
While missing both Wednesday and Thursday practice is not unusual it is now time to raise your attennas and start thinking of alternatives, like Trickster and wisfinfan05 are preparing to do. That said, missing both practices is not the end of the world either. Hammys are a rest em is good type of injury. You spend your time having the trainers carefully stretch you, do some bicycle work and whirlpool duty. This is all designed to help you heal and keep you flexible and work the hammy with out straining it further. Now most coaches have as a general rule that you must practice Friday to play Sunday. Now this is more of a principle than a rule as a lot of players still end up out on the field come Sunday. But Friday practice or non-practice usually provides more intel as you will generally find out if a player is out or a Game-Time Decision. Like I said many players who don't practice Friday do end up playing on Sunday. The rule/principle has many variations, such as how important a cog the players is too the team and the nature of the injury. Brian Westbrook had knee problems last year and was a GTD often. His knee would swell up if he practiced and swelling like that takes several days to go down. So he didn't practice all week long and come Sunday they would check the knee out and if it looked ok then tape him up and give him a shot and let him play.
Walter has started jogging which is a step above riding the Bicycle as the bike riding is to keep you flexible and yet support your weight so you are not running on it. A lot of sites will point out that he is Jogging and not cutting which is true. But you don't want him to be cutting on a Wednesday or Thursday as every day of healing is quite frankly a day of healing and hammys are a rest is the best type of injury. Hammys also range wildly in degree. You have a went down like he was shot while on the field Hammy. This is usually followed by an MRI and a report on the severity of the hammy and a prognosis of missing weeks. Then you have a pull up short type of hammy and walk back to the sideline with a gimp. This is like Walters hammy. No MRI and put on a rest is best routine for as long as possible with a day to day tag. A general hammy is hard to come back from in the next week and is more of a concern during the season. But being a pre-season injury there was the luxury of an extra weeks rest.
I could go on and on but this is some basic observations that comes from years of watching injury reports for my fellow FF owners.