Ducasse is an interesting signing, versatile dude who can play several positions. Here is how many games he started and how many sacks he gave up...
2010 - 2 games, 0 starts - 0 sacks
2011 - 16 games, 1 start - 0.5 sacks
2012 - 16 games, 0 starts - 1.25 sacks
2013 - 16 games, 4 starts - 2 sacks
2014 - 13 games, 6 starts - 3.5 sacks
2015 - 16 games, 11 starts - 2.25 sacks
2016 - 10 games, 8 starts - 1.5 sacks
2016 was by far his best year, granted I don't have stats for pressures given up or anything on rushing yards. Still, this may be a better pickup than given credit for.
If Cyrus is viewed as a LT only, I wouldn't be shocked to see a trade.