The surface was upgraded to Field Turf in 2004.
What kind of turf are they using at the dome? I know that the astroturf was used since it opened but when Ford Field was built they had a new type that was closer to the look and field of real grass that was supposed to be easier on the players joints. I remember hearing Red saying that he was going to make the switch but don't recall ever hearing if he did.
During its early years of operation, the field at the Metrodome was surfaced with SuperTurf, which was disliked by both football and baseball players as being too hard. This surface was upgraded to Astroturf in 1987, and in 2004, the sports commission had a newer artificial surface, called FieldTurf, installed. FieldTurf is thought to be a closer approximation to natural grass than Astroturf in its softness, appearance, and feel.