H. Keepers can be kept for 3 years at their original draft value. After 3 years, if they have a draft value of round 11-20, their round value would have 5 rounds deducted from it. If the player has a draft round value of 1-10, than 3 rounds would be deducted from it. This would happen each year until the player would eventually be worth a first round draft pick.
Here's the list of players this would effect if kept for next season. I included at the end of each line what their numbers for next season would be with the R_Y_ format.
Clayton Kershaw, SP (Round 1, Year 10) - R1Y11
Chris Sale, SP (Round 1 - Year 7) - R1Y8
Giancarlo Stanton, OF (Round 1 - Year 9) - R1Y10
Freddie Freeman, 1B (Round 1 - Year Eight) - R1Y9
Mike Trout, OF (Round 1 - Year Eight) - R1Y9
Bryce Harper OF (Round 1 - Year Eight) - R1Y9
Jose Altuve 2b (Round 1 - Year 3) - R1Y4
Paul Goldschmidt, 1B (Round 1 - Year Eight) - R1Y9
Max Scherzer SP (Round 1 - Year 7) - R1Y8
Cole Hamels SP (Round 1 - Year 11) - R1Y12
George Springer, OF (Round 4 - Year 5) - R1Y6
Nolan Arenado, 3b (Round 4 - Year 5) - R1Y6
Antony Rizzo, 1b (Round 4 - Year 7) - R1Y8
Manny Machado, 3b/SS (Round 4 - Year 7) - R1Y8
Josh Donaldson, 3b (Round 7 - Year 6) - R4Y7
Anthony Rendon, 3B (Round 7 - Year 6) - R4Y7
Corey Kluber, SP (Round 7 - Year 4) - R4Y5
Charlie Blackmon OF (Round 10 - Year 5) - R7Y6
Francisco Lindor, SS (Round 10 - Year 5) - R7Y6
Mookie Betts, OF (Round 10 - Year 5) - R7Y6
JD Martinez, OF (Round 10 - Year 5) - R7Y6
Jacob DeGrom, SP (Round 10 - Year 5) - R7Y6
Kris Bryant, 3b/OF (Round 10 - Year 5) - R7Y6
Khris Davis OF (Round 11 - Year 3) - R6Y4
Joey Gallo 1b/OF (Round 10 - Year 5) - R7Y6
Carlos Correa, SS (Round 13 - Year 4) - R8Y5
Trea Turner, SS (Round 15 - Year 4) - R10Y5
Willson Contreras, C (Round 17 - Year 3) - R12Y4
Carlos Martinez, SP (Round 15 - Year 4) - R10Y5
Kyle Schwarber, OF (Round 15 - Year 4) - R10Y5
Wil Myers, 3b/OF (Round 15 - Year 3) - R10Y4
Corey Seager SS (Round 15 - Year 4) - R10Y5
Noah Syndergaard SP (Round 15 - Year 4) - R10Y5
Gary Sanchez, C (Round 20 - Year 3) - R15Y4
Alex Bregman, 3b/ss (Round 20 - Year 3) - R15Y4
Jose Ramirez, 2b/3b (Round 20 - Year 3) - R15Y4