Serge Savard, Ken Morrow and Glen Wesley were the first 3 names that popped in my head when I saw this topic.
Wesley was the first I thought of. He was the definition of a reliable and quiet d-man. He was never an elite offensive guy but in his first 7 seasons in the league (all with boston) he scored 307 points in 537 games (0.5716 ppg) averaging 43.85 points per season (46.87 adjusting for injuries). Not half bad numbers at all. Now, I didn't start watching hockey until the 1993 season so I sorta missed all this, but then when he went to Hartford he seemed to almost instantly change his game and became a top notch shutdown guy and ditched the offense only scoring over 30 points 1 more time (32) and another 230 over the next 13 seasons. An average of 17.6 points per season. His plus minus stats aren't amazing (+66) but it ain't too bad considering he played on a lot of bad teams and was almost always given the task of shutting down the other teams big guns. Just glad he finally got his cup in 2006. A true unsung hero... until this post anyway