So was Nate Newton.
Actually, Nate Newton, Mark Tuinei, Mark Stepnoski, and Kevin Gogan were all part of the 1 win 1989 Dallas Cowboys that were the laughing stock of the league.
Nate came to the Cowboys in 1986 and was part of a few very bad teams. People made jokes about him being fat for years. Then, suddenly the talent around him rose and Newton went to the pro bowl in 1992, 1994, 1995, 1996, 1997 and 1998 with the '94 and '95 seasons being All-Pro.
Stepnoski was drafted in Johnson's first year in 1989. He didn't do much to help until the talent around him matched his own. Then, he went to the pro bowl in 1992, 1993, 1994, 1995 and 1996.
Kevin Gogan arrived in Dallas in 1987. Like Newton, he was part of some very bad Cowboy teams that were made fun of for years. Once the team improved he went to three pro bowls in 1993, 1997, and 1998 and was listed as second team All-Pro one year.
Mark Tuinei came to Dallas as a defensive tackle in 1983. He was there through the bad ending of the Landry regime and the very bad beginning of the Jimmy Johnson staff. Was looked at as not that good until, like the other's on this list, the team arrived in prime time. He was a pro bowler in 1994 and 1995.
It isn't really uncommon for guys to be completely overlooked until the team gets truly good, and then everyone starts noticing they're doing a damn good job.
I'm sure Free has improved and that having a dominant OL around him helps... but the guy isn't a bad player at all. He's smart, consistent, works hard, and is the leader of what is the best OL in football.