They have not had a winning season without Parnell since 2007.
In 2017 they got to the ACF Championship and barely lost to the Patriots by 4 points.
Prior to signing Parnell, Jaxonville's biggest issue had been their OLine.
Jaxonville had 2262 rushing yards in 2017 after averaging less than 1500 from 2011 until Parnell was signed.
Parnell was injured the following season and Jaxonville fell apart going from the AFC Champion to a 5-11 season.
Obviously Jaxonville signed a couple of other good players when they signed Parnell, but Parnell was a big part of their success.
Parnell got the most playing time with the Cowboys in 2014. With Parnell at RT and Leary at LG, that lineup had the best performance of any Cowboys OL in more than a decade before and better than anything since.
Parnell played 7 games including the 2 playoff games and gave up a total of 1 sack.