The past few weeks have been very exciting for Buffalo Bills fans. The Bills have added dynamic new offensive players, while also re-signing their primary unrestricted free agent, Jerry Hughes, to a long-term contract extension. The coffers of Kim and Terry Pegula have seemed bottomless, as demonstrated by the Bills' most recent decision to make an offer to Charles Clay that will make him the fourth-highest paid tight end in the league. All of this spending should hopefully mean that the Bills team which takes the field in 2015 is an improvement over the 9-7 outfit that had a crack at the playoffs as late as December 21 last year.

Despite the big moves, Bills fans are still well aware that some of the primary pieces that led to that 9-7 record last year are entering the final year of their respective contracts in 2015. How will the Bills' offseason spending spree affect their ability to retain many of their core young players a year from now?

According to Spotrac.com, the Bills currently have around $110.5 million already committed to 45 contracts on their 2016 salary cap. With the expected signing of Clay, and expenditures such as offseason per diem workouts (about $500,000) and practice squad contracts (about $1.1 million), it is unlikely the Bills will roll over much, if any, of their dwindling 2015 cap space to 2016.

If the trend of the last two years continues, it can be estimated that the 2016 NFL salary cap will once again increase $10 million, to a total of $153.28 million. That number would mean that the Bills should have around $42.5 million in cap space. Unfortunately, that money will disappear much faster than Bills fans will like.

Obviously, speculating a year in advance means assumptions and predictions must be made, so I figure it will be easier to just lay them out individually:

Projected 2016 cap deductions

Clay cap hit: ~$12 million. ESPN's James Walker has reported that Clay's 2016 cap hit will be around $12 million.

Stephon Gilmore option year: $11.082 million. Buffalo will inevitably exercise their option for the fifth year of Gilmore's contract, meaning that his 2016 salary will equal the 2015 transition tag for a cornerback, or $11.082 million. Although the Bills did not (or have yet to) do this with Marcell Dareus when he was in the same situation, a long-term extension for Gilmore that will lower this figure should be pursued. But with Byron Maxwell receiving over $10 million per year and the cornerback market overall rebounding nicely, it is fair to assume Gilmore will demand a hefty (and if he plays like he did last year, deserved) contract.

2016 rookie allocation: ~$4.8 million. With the Bills once again having a first-round pick in 2016, their rookie pool will be higher than the about $3.23 million that is required for 2015.

Nickell Robey RFA tender: ~$2.6 million. This estimates an increase from $2.356 million to $2.6 million for a second-round RFA tender. Robey was excellent in Mike Pettine's scheme as an around the box slot corner, and it is fair to assume new coach Rex Ryan will utilize his skills well, therefore desiring to keep him around another year. The other notable Bills currently on the roster that will be restricted free agents in 2016 are Chris Hogan, Bacarri Rambo, Ty Powell, Marcus Thigpen, MarQueis Gray, Stefan Charles, and Corbin Bryant. Under this assumption, all of these players will become unrestricted free agents for 2016.

Percy Harvin dead money: $2 million. As the contract has dummy voidable years, the $2 million in prorated signing bonus money will accelerate onto the 2016 salary cap.

Kyle Williams new money: $1 million. Spotrac has not applied the new terms of Williams' contract, which increases his 2016 cap hit from $7 million to $8 million.

Duke Williams proven performance escalator: $945,000. Barring an injury, it is very likely that Williams will play in well over 35 percent of defensive snaps, therefore earning a raise (again, using the estimated restricted free agent tender of $1.62 million) of $945,000.

Current cap: $110,524,256 (based on Spotrac.com)

+ $12 million (Clay)

+ $11.082 million (Gilmore)

+ $4.8 million (rookie pool)

+ $2.6 million (Robey)

+ $2 million (Harvin)

+ $1 million (Kyle Williams)

+ $945,000 (Duke Williams)

$144,650,956 (projected 2016 cap total)

Operating under the above assumptions, all of which are either seemingly assured of happening (Clay, rookie pool, Williams extension, and Williams escalator), conservative assumptions (only one RFA tendered), or unlikely to change all that much (even a Gilmore extension, unless an enormous hometown discount is granted, should not be expected to carry a cap hit much lower than $8 million), the Bills' 2016 salary cap space is already significantly accounted for.

$153,280,000 (2016 cap estimate)

- $144,650,256 (Bills projection)

$8,629,744 (projected cap space)

This is the list of the Bills' upcoming free agents next offseason:

QB Matt Cassel

RB Fred Jackson

RB Bryce Brown

WR Percy Harvin

OT Cordy Glenn

OG Richie Incognito

DT Marcell Dareus

LB Nigel Bradham

CB Ron Brooks

While estimating with any accuracy free agent contracts a year beforehand is likely a fruitless task, even general estimates would show that around $8.6 million in 2016 cap space will not be suitable to bring back Dareus (the first-year cap hit for the absolute basement floor of Dareus' value, Gerald McCoy, is around $14 million), never mind the rest of the Bills' core young players.

There are, of course, a few things the Bills could do to free up more space next year.

Cuts: Leodis McKelvin, Chris Williams, Manny Lawson, and Kraig Urbik: $10.25 million. Although Urbik just took a pay cut, the Bills could still cut one or two of these players this offseason, so their not being with the team in 2016 does not seem far-fetched.

Mario Williams re-structure: $6.5 million. This move could also happen soon to accommodate the Bills' 2015 salary cap needs, though that seems unlikely. Williams has $14 million in combined 2016 salary and a roster bonus, $13 million of which could be converted to a signing bonus - effectively ensuring Williams plays out his Bills contract while saving the Bills $6.5 million in 2016 cap space, while increasing his 2017 cap hit accordingly.

$16.75 million (possible 2016 cap savings)

+ $8.6 million (projected Bills cap space)

$25.35 million (adjusted Bills projection)

As shown, the Bills can significantly increase their 2016 spending power by making some easy cuts and restructuring Mario's massive contract. What remains to be seen is whether cap space around $25.35 million will be enough for the Bills to retain the three primary free agents listed above - Dareus, Glenn, and Bradham - while still having some flexibility to find another stopgap veteran quarterback option and the interior offensive line help that will most likely be necessary with Incognito hitting free agency and the Urbik-Williams duo being released. The Bills can obviously alleviate some of these concerns by drafting well in both 2015 and 2016, as the unknown upside missing from all of these projections is that draft picks already accounted for in terms of the draft pool cap space can slot in and replace veteran salaries.

Summarizing, the Bills' 2015 offseason moves, although exciting, will definitely place the team in a much more precarious salary cap situation next year than they have been in during recent memory. With the salary cap projected to continue rising, Mario Williams' massive contract coming off the books after the 2017 season, and no franchise quarterback-type salary for the foreseeable future, the situation is not yet truly dire, but the Bills will certainly be handcuffed by the salary cap in the upcoming years more so than they have been in the past.