In a vacuum, the Packers have several candidates arguably worthy of an extension.  I can make a case for Blake Martinez, and to a much lesser extent, Kenny Clark and Dean Lowry, but on the whole I do not think the Packers should extend anybody at present.

The other candidates for an extension include Daniels, Bulaga, and Fackrell.  Players who will be unrestricted free agents after this season include Allison, Tramon Williams, Crosby, and if they make the team in 2019, Spriggs, and Trevor Davis.

Let's take a quick look at the Packers available cap space for 2019.  At this point, the Packers should be looking at a two-year window since any extension would affect the team's cap hit in 2020 as well.

Green Bay's cap space currently is estimated by Over The Cap at $9 million and by Sportrac at $8.9 million under The Rule of 51, which ends when the first regular season game is played.  At that time the last two roster spots (a minimum of $990,000) also will count along with the practice squad ($1.36 million).  Every year the IR and other costs reduce cap space as the season progresses.  The Packers cap space likely will be reduced by about $175,000 or so when Sternberger signs.  Working numbers might be $8.75 million now and $6.5 million when the season starts.

The Packers could still sign a free agent or two, either now or later this summer. Signing someone like Ibraheim Campbell (if healthy) or some other free agent(s) for depth is quite possible.

My objection to extending any current players fall into four categories: 1) Extending any player reduces the Packers' cap space in 2019; 2) Green Bay might need cap space to acquire more players for this season; 3) Extending a player now generally means a bigger cap hit will fall in the 2020 season when cap space is also tight; 4) The player still needs to prove something or there are possible internal replacements.  The player might wish to bet on himself and is not interested in an extension.

Kenny Clark: I am happy with Clark's $2.978 and $7.69 million cap hits in 2019 and 2020, respectively.  Two full seasons of control is a lifetime in the NFL.  I am not interested in guaranteeing Clark's health for two years, which an extension with a large signing bonus would do.  [The fifth year option is only a partial injury protector and it can be rescinded.] 

I concede that Clark is elite and is likely to remain so.  His 2019 cap hit probably would only increase by a million or two.  It may be that he will improve, so extending him now might look like a bargain later.  But he is already in $12 million per year territory.  If he starts to look like Aaron Donald, that will be a good problem to have.  Clark does not fall into any of my four objections: extending Clark would mean taking on too much risk.

Daniels and Bulaga: Both are good players who will be 31 in 2020 and have had some injuries. Bulaga's streak of 136 pass blocking snaps without allowing a pressure is the longest among offensive linemen (excluding centers), per PFF.  Daniels' statistics per snap decreased significantly but the film gurus continued to hold him in high regard.  Both players have fairly large base salaries, so extensions could free up cap space in 2019.

However, the Packers have potential replacements for Daniels in Gary, Montravius Adams and Keke.  I would prefer to see if any of them end up playing three technique and look good at it.  Zadarius Smith moving inside at times could also soak up defensive line snaps.  I do not see an internal replacement for Bulaga.  Turner sounds like a significant downgrade.  Adding years onto Bulaga's contract is simply a gamble on his health.  

Fackrell, Allison and Crosby: I would like to see these players produce in 2019 before paying them.  Ditto for Spriggs, Lewis, Davis and Bibbs.  Fackrell and Allison might not be interested in extensions.  Allison has a good chance to get enough snaps to produce solid numbers.  Another 10-sack season from Fackrell might price himself out of Green Bay, but I am wondering just how many snaps he can expect to get. 

Blake Martinez: I would like to watch him (and Burks) for another year.  His coverage improved a lot but I thought his run defense declined.  Were those things one year blips?  That said, he is at least a legitimate starter and at present there is no internal replacement.  A good case can be made for extending him.  Using Trevathan as a comparable, I would be interested in Martinez at about $7.5 million AAV, but some have suggested he will command more money.  Extending him likely increase his cap number by a couple of million in 2019.

Dean Lowry: He had a quietly good season with career highs in tackles (45), sacks (3) and seemed to establish himself a a quality rotational lineman.  I would dislike losing both Daniels and Lowry in the same season.  Still, I wonder how many snaps he will get in 2019 with Daniels and Clark back, Z. Smith and Gary moving inside, and Keke and Adams pushing for playing time.  This time it is not the player I need to see more from but rather how this defense is going to function and how Keke, Gary and Adams look.

2020 Cap:

The cap has increased by about 6 percent for the last two years.  Another such increase would mean a $200 million cap limit.  Overthecap lists the Packers with $16.16 million in cap space using a $200 million team cap limit with 48 players under contract.  There will be three more players.  Also, Sternberger is not included: his cap hits will exceed the minimum.  OTC does include Clark at $7.69 million.  After adjusting, the Packers should have about $14.3 million in cap space, plus any rollover from 2020.

There is wide speculation that the Packers will release Jimmy Graham, picking up $8 million in cap savings.  That is not a foregone conclusion, though, since it would leave just Sternberger and Tonyan at the tight end position.  A pay cut seems plausible as well. 

It is possible that the Packers will release Lane Taylor ($4.55 million cap savings) if Jenkins and Turner work out, or if Taylor regresses.  That would give the Packers a working number of between $14.3 and $26.55 million plus any rollover. 

Scanning the list, only Linsley ($8.5 million) and Zadarius Smith have more than $2 million in cap savings.  Is fourteen to twenty-something million too little, just sufficient, or a comfortable amount to sign the 2020 draft class, keep the necessary players and acquire talent?  That depends on one's view of the potential internal replacements for Daniels, Bulaga, Martinez, Lowry, Crosby, Fackrell, Allison, Tramon Williams, Spriggs, Graham and Lewis. 

Bakhtiari will also be in a contract year in 2020 at age 29, which makes him a prime candidate for a large extension.  His cap number is $14.2 million for both 2019 and 2020.  The Packers could save a few million in cap space by extending him in 2019, and perhaps break even in 2020, but it seems a year early to extend him.

The Packers should retain flexibility by not extending any players at least through September.  Some time during the season the Packers could consider extending a player or even two when they see the players and know exactly how the cap looks.