(1) Had to be Friday "each Friday, not later than 3 P.M. E.D.T.," (2) 10 days? (3 see above) At this point, it seems obvious the Astros had no interest in making a claim before Lee's injury.
I think the Friday thing is just a weekly summary of activity that the league has to send out to all the teams.
This is from a
Steve Phillips article from 2005, so consider the source.
"Players remain on waivers for a period of 47 business hours. (The waiver period starts at 2 p.m. ET on the given business day and ends at 1 p.m. ET two business days later.)
A waiver claim can be submitted anytime during the 47-hour period a player is on waivers. There is no advantage to submitting the claim in the first hour or the 47th hour.
Major League Waivers are revocable, meaning that if a player gets claimed, his club can pull him back and keep him if they do not reach a deal with the claiming club. If a player is pulled back off of this type of waivers, he cannot be placed on them again for 30 days.
If a player is claimed on waivers, the team which claims the player has 48½ hours (from 1 p.m. ET on the day he was scheduled to clear waivers to 1:30 p.m. ET two business days later) to make a deal with the player's club or he is automatically pulled back off of waivers."