He was probably very bad
FanGraphs has him at 137 runs worse than an average SS for his career.
2003 was actually a good year for him. Again, Fangraphs has him at -3.7 runs (but in just over 1000 innings)
In 2002 and 2004 he was pretty close to average.
Before and after that time period he was frequently around 10 (or more) runs worse than an average SS
https://www.fangraphs.com/players/de...stats#fielding
Edit:
I disagree with slugga, don't look at fielding percentage. That's like *only* looking at batting average to figure out if a player was a good hitter - it leaves out a lot of information.
Look at ZR. It'll give a much more comprehensive view of a player's defense.