What kind of contract will Nick Castellanos command?

Nick Castellanos was arguably the biggest impact trade deadline acquisition in 2019. Coming to a playoff contender gave him a jolt, as he hit 21 doubles and 16 home runs in just 2 months as a Cub. He fit right into the Cubs lineup, making them more dangerous than before. He openly loved Wrigley Field, even taking his girlfriend on a picnic in the outfield. Cub fans loved him and his "every day is opening day" attitude. I went to a game on September 14th and spotted two Castellanos jerseys in the stands. He is Big Stick Nick (BSN).
Will BSN come back to the Cubs? Some of the signs are there.

However, as always with free agents, it usually comes down to money. Castellanos is going into his age 28 season, arguably his career prime, and is a free agent. He has a career 113 wRC+, with a .797 OPS. He was a slightly below average hitter his first two seasons, then a 121 wRC+ average for the last 4 seasons. He played most of his career at 3B, then shifted to right field in 2018 (ironically partially because of former Cubs prospect Jeimer Candelario). He's never been known for his glove, and is often thought to be a defensive liability. Castellanos doesn't walk a lot ( 6.4 career BB%), but does hit for decent power (about a .500 SLG in the last 4 years). Last 4 years average OPS is .838. Overall, he ranks as the 49th best hitter in baseball from the last 4 seasons.
Indicators from the past: There have been similar bats on the market in the past that could give us a clue as to what kind of contract BSN might be looking for.
In 2019:
A.J Pollock 5 years/$60 at age 31 off an injury filled year.
Michael Brantley got 2 years/$32 at age 32
In 2018:
JD Martinez got 5 years/$110 at age 30, after being a huge deadline acquisition.
Jay Bruce got 3 years/$39 at age 31
In 2017: Josh Reddick got 4years /$52 to stay with Houston at age 30
In 2016: Justin Upton got 6 years/$132 at age 28
None of these bats are an exact comparison. It seems like very few hitters hit the market before age 30. Some that do were at a different level (think Harper, Machado, and Heyward), and so I'm not sure that helps us determine BSN's value. It seems like younger players can get longer deals, but it does not seem like teams are willing to pay much more than $15 million per year for non-elite hitters.
Who are the other bats in the FA market?
Being the best bat in a free agent market can lead to an increased contract. If a team needs the best, they'll often overpay. Castellanos has an advantage here. Anthony Rendon and Josh Donaldson both rank above him in OPS for 2019, and that's pretty much it in terms of big contract possibilities. Among incoming free agents, BSN ranks 6th in home runs, 9th in RBI, and 2nd in hits. He's also 28, comparatively younger than most other bats. That makes him a prime candidate for a longer deal. Josh Donaldson is an odd case, having to sign a 1 year deal after a terrible 2018 contact year. He'll be 34, but still figures to get a decent deal. After Washington reportedly offered Rendon $210 million for 7 years, it's very uncertain what kind of offers Castellanos can get.
Will there be a bidding war?
Castellanos kind of fell into the Cubs laps for the trade deadline in 2019, as there was not huge demand for him. He only cost the cubs 2 top 30 prospects (not much in a barren system). Some of the prime candidates for over pay for players (Yankees, Dodgers, Red Sox) already had full outfields, and still are pretty much set in free agency this year. Castellanos doesn't seem to be a splashy bat, so there may not be widespread interest in his services. The lack of glove impacts his value to NL teams in a potential long term deal.
Pronkediction (Pronk prediction): Much like Josh Reddick for Houston, I think the Cubs front office wants to keep Castellanos around. I think this could go one of two ways. 1: Short term deal: Castellanos can't get big offers, and takes a 1 or 2 year prove it type of deal for $15 million or so per year. This allows him to re-enter the free agent market if he can step up his production. 2: Long term deal: This could be his only shot at a long term 5-7 year type of deal. He could get a J.D. Martinez like $70-$120, averaging $11-$17 million per year. Opt outs and no trades can be a factor as well.
I think BSN comes back to Chicago on a 5 year deal worth around $85 million. I think he pushes for an opt out after 2 years so he can re-enter the market if he becomes an elite bat. There's a chance that if nobody else is really bidding for him, he could sign for under $13 million per year on a shorter term deal.
We'll see!