49ers salary cap: Beginning the look at 2015 free agents

I want to start a new series on what to expect market wise for upcoming 49ers free agents. The 49ers have a whole host of potential free agents, but I'm going to focus on the pending free agents most visible on the 49ers radar.

We'll start this week with offensive guard Mike Iupati and offensive tackle Anthony Davis. Both were first round picks in the 2010 NFL Draft, and both have been key pieces of what is believed by many to be the top offensive line in the NFL.

Iupati received a five-year deal, worth $18.25 million. This deal included a $480,000 signing bonus, and an option bonus worth $4.35 million. Those bonuses are prorated over the life of the contract for cap purposes. The option bonus was given in year two of his contract. Iupati, voted All Pro and Pro Bowl, will likely seek between $7 million and $8 million per year. Let's break down some contracts recently given out to guards that would point to this potential contract figure.

In 2012, Tampa Bay Buccaneers guard Carl Nicks received a five-year contract, worth $47.5 million. This included a $6 million roster bonus in year one, and guaranteed money for his 2012 and 2013 base salaries. Nicks recently restructured his contract to free up cap room for this offseason, so it is hard to gauge his current terms exactly. However, his entire base salary was guaranteed, plus he has a new option bonus of $12.865 million paid in 2012 when he redid his deal. I don't expect that in an option bonus, but it isn't outrageous to think Iupati would get an option bonus at some point in his new potential contract.

Next up is a signing this offseason by the Tennessee Titans. They added Andy Levitre from the Buffalo Bills, signing him to a six-year deal worth $48.6 million. This included a $10.6 million signing bonus, and $2.5 million in guaranteed money in his first year base salary. It isn't far-fetched to see Iupati potentially getting a bigger signing bonus than what NaVorro Bowman and Ahmad Brooks received in their new deals this last year.

If you compare these deals, I would expect a similar deal to Levitre. I could see something more cap friendly, with a $10 million signing bonus, prorated over five years at $2 million a year, a second-year option bonus at around $5 million, prorated over four or five years, depended on the extension length.

Next up is Anthony Davis. The 49ers right tackle signed a five year deal, worth $26.5 million, which included a $1 million signing bonus, and an $8.5 million option bonus due in year two. His deal actually runs through 2015, but will void after 2014, and leave a dead money hit of $1,866,670 for the 2015 season.

There is the possibility to push the money into 2014, but that wouldn't be the best idea. 2014 is a key offseason as the 49ers will be dealing with Donte Whitner, Justin Smith and Tarell Brown as their main free agents on the defensive side of the ball. The offensive side of the ball will include Jonathan Goodwin, Anquan Boldin and Mario Manningham as free agents.

The only recent comparable contract is Sebastian Vollmer's new deal with the New England Patriots. Vollmer signed a four-year deal with a max value of $27 million, but a base value of $17 million. He received a $7 million signing bonus, which would be a good starting point for a deal for Davis. Vollmer also has incentives for offensive snaps in each season. These include $750,000 for 90% in 2013, $1 million for 80% and $1 million extra for 90% in 2014, then $750,000 for 80% and $1.75 million for 90% in 2015, and the same for 2016. He also has $250,000 in Pro Bowl incentives for each season.

As for roster bonuses, Vollmer can earn up to $62,500 for each game in 2015 and 2016, at a total of $1 million each season. In 2014, he would receive a $1 million roster bonus, due on day three of the 2014 new league year. This is based on him playing in 80% of snaps the previous year. The same goes for 2015 and 2016, based on the same 80% snaps the previous year.

Something in that range is fair market value for Davis. I can see a five-year deal, with a $7.5 million signing bonus, just like Bowman and Brooks got in 2012. Additionally, I could see roster bonuses in the $750,000 range, which would equal Bowman and Brooks. Additionally, we could see an option bonus, similar to Bowman, and incentives, similar to Bowman and Vollmer.

I hope the 49ers do indeed extend both Iupati and Davis, as they are vital for the success of the 49ers offensive line.

Please check back in the coming days for comparables on Colin Kaepernick, Michael Crabtree and Aldon Smith, among others.