The Clippers signed Hayes to a 1 year, non-guaranteed contract (as reported by NBC Sports), so ultimately, they retain their flexibility, while bringing in a veteran big man who, although undersized, has been a serviceable center in the league for 10 years. For his career, he has averaged 3.7 points and 5 rebounds while playing for the Houston Rockets, Sacramento Kings, and Toronto Raptors last season, where he appeared in 29 games.
Hayes, if he makes the roster, will a toughness at the 4 and 5 position that the Clippers have lacked since the departures of Reggie Evans and Kenyon Martin after the 2011-12 NBA season. Hayes became available after issues with his agreed upon contract with the Rockets fell through due to salary cap issues. With the addition of Hayes, it looks as though Glen Davis will not be with the Clippers next season, as they have 14 guaranteed contracts, and Hayes looks to be his replacement.
The fact that the Clippers were able to sign him to an non-guaranteed contract leave the team with a lot of flexibility, and once he becomes available for trade (if he makes the roster), he will be able to assist in salary matching, if and when the Clippers do make a move. If he makes the roster, more than likely Jamal Crawford will be with the team for the first half of the season, as it wouldn't make sense to trade him without the ability to include Hayes, which would allow for them to bring back more salary.