Redskins Salary Cap Status 2018

[FrenchSkin]

I have a question for you Schneed (or somebody else well aware of these cap matters):

Per OTC, the Skins will have 23M cap space available in 2019 (1.4M per spotrac. They assume 2019 salary cap to be 177M, same as 2018, OTC assumes 190M, which seems more plausible, spotrac includes Scherff's 12.5M 5th option in their calculation, OTC doesn't, which also makes more sense IMO).

Both cases, the Skins will be bottom of the league in cap space available (29th per OTC, 30th per spotrac).

My question is: if we extend players this season (for say, Brandon Scherff), at what point do we have to be under 2019 cap? Are we allowed to sign contracts that would put us over the cap in upcoming years, and find ways to get back under the cap when time comes?

The Jags will be way over the cap in 2019 (16M per OTC, 44M per spotrac), so this has to be legal but the Skins cautious approach in FA made me wonder about this.