Gray, 34, son of former Leeds defender Frank Gray, has returned to the club where he began his career and has signed a one-year deal following his release at the end of the season from Barnsley.
Gray made 29 appearances for Leeds at the start of a 17-year career that has taken in 11 clubs and over 500 senior appearances.
Ashdown, a regular at Portsmouth last season, has joined up with the Leeds squad in Cornwall after agreeing a deal to join on a permanent basis.
The 31-year-old has made 163 career appearances, the majority coming during two separate spells at Fratton Park. He started his career with hometown club Reading and has also had spells at Bournemouth, Rushden & Diamonds and Norwich.
Manager Neil Warnock has now drafted in six summer signings with Jason Pearce, Adam Drury, Paul Green and Paddy Kenny having already arrived at the club.
Jamaica is in need of a win against the U.S. Get the jersey of the Reggae Boyz.
England will debut their new away jersey against Brazil at the Maracana Stadium on Sunday. Get in the Gear
Support the USA national team with an official 2013 Centennial soccer jersey from Nike. Its Official.
The USA will wear their blue away jersey against Jamaica in their World Cup qualifier on Friday night.
The adidas Nitrocharge is the most talked about new cleat in years. It was released on May 15 and will take your pitch by storm.
Neymar's move from Santos to Barcelona is no doubt the biggest summer transfer.
Manchester City will try and win back the Premier League title with this new soccer jersey from Nike!
The Nike Hypervenom is the latest cleat silo from Nike. It will change your game and is worn by the game's top players.
Barcelona will wear this new home soccer jersey next season. They also have a new away jersey. Get them both.
Germany is one of the top teams ever and they will play the US on Sunday.