Slater played 16 games in 1992 and went on to play until 95, which he was 41, but he played in only 8 games in 93, 12 games in 94 and one game in 1995 and as I recall, after the 92 season, the decline happened fast especially from an injury standpoint.
Andrew Whitworth is in more aerobic shape than Slater and Whitworth makes a big deal about that, but IMO, this will be Whit's last year because he's been very fortunate with injuries and is a family man, however, I could see him working in the Ram organization.