Under our current rules I believe the only extension Cabrera could be given is $19m per year for 4 years. An extension of less than his current $19m would have a maximum limit of 2 years. An extension of $19m has a minimum limit of 4 years.
We are governed by the following rule when signing a player to an extension that is less than his present contract:
A player may be given an extension that is less than their current salary. However, such an extension has three restrictions.
1) The eligibility period for granting a player an extension below their current salary is only in the last year of their contract.
2)
On top of the minimum and maximum years for contracts, the longest this type of extension can be is two years.
3) New salary may be no less than 70% of previous salary. Therefore, a player with market value of $2.5m, current one-year deal of $5m, can have an extension for two years equal to $3.5m (0.7 * 5 = 3.5).
The key is the first part of restriction #2: "On top of". These words supercede the minimum and maximum years for a contract by stipulating that "the longest this type of extension can be is two years." The 70% rule is set up to safeguard signing a player in the last year of his contract to a long-term contract at a reduced price by limiting it to two years.
For example, on the Giants, CI Adrian Gonzalez had an expiring contract of $18.0m which was set to expire in 2015. In the off-season, in the last year of his contract, he was given an extension of $15.0m, which under normal circumstances would have a minimum length of three years and a maximum of five years. However, because of the 70% two year clause, the contract was limited to only two years, thus preventing the Giants from having him for an additional one to three years at a reduced price.
Another example is a player like SP Cain, Matt, $9.5m (2015), 30 year old SP who has battled injuries that last two years. He is ranked #163 in 2014 and #203 in 2015, which would normally be an extension of $1.0m. Due to the 70% rule, his minimum contract has to be $7.0m. Now under the the Minimum/Maximum Limits, without the 70% rule, by the numbers, his contract could be two years minimum or four years maximum. If by chance he regains his previous form, which is debateable, but certainly not impossible, consider this. In 2012 he was ranked #12 ($14.0m) and in 2013 he was ranked #40 ($9.0m). Without the two year clause, he "could be" a bargain if he regains his 2012-13 form or he could be an albatross and be a candidate to be Released under Contract.
This two year clause only applies to players who are going to be signed to a contract which is less than their current contract and is the rule that supercedes all other extension provisions.