Roddick, a four-time champion, hurt his foot in the third game after running back on a lob from Blake. After failing to hit the ball between his legs, Roddick stumbled on the edge between the grass court and surrounding concrete.
His ankle and foot were taped after Blake had held serve for 4-3, but Roddick retired after the next game.
It was not immediately clear whether the injury would affect his participation at Wimbledon, which starts June 22.
The top-seeded Murray is trying to become the first British winner of the pre-Wimbledon tournament since Bunny Austin in 1938.
“I thought it was a good match,” Murray said. “I served very well in the first set. The second set was very close with long rallies and close games and I was obviously happy to win in two sets. It was a very tough match.”
Murray put Ferrero under pressure right from the start, breaking to lead 1-0 when his opponent netted a backhand.
Murray then raced to a 5-1 lead, breaking a second time at 3-1 when a forehand from Ferrero clipped the net cord and landed long.
In the second set, Ferrero saved five break points in his first two service games to take a 2-1 lead, but Murray broke to go up 4-3 before closing out the match.
