Ware struggled during 2013 with injuries to his quadriceps, which limited him to just 13 games for the Cowboys as they missed the playoffs for the fourth straight season.
Garrett told the Fort Worth Star-Telegram: "He's missed a lot of practice time over the last couple of years because of all these injuries, and that's something that really can impact a player, even a player of his calibre.
"You need to practice. We've got to get him to the point where he's healthy and he can practice and he can get himself ready to play the way he's capable of playing."
The 31-year-old had the lowest sack tally of his career with six in the 2013 season.