Blas Castano

RP · R/R · age 28 · COL

OCTOBER OK

Roster status
ACTIVE
Service thru 2025
0+007
Service now / projected
0+109 / 0+122
Option years left (2026)
2 (using one in 2026)
Assignments left this season
1 of 5
Contract (2027)
PRE-ARBITRATION / AUTO-RENEWAL
Acquired
Waivers (SEA) Apr'26
Outrighted / DFA'd before
0 / 1
Contract
none listed

Next 90 days, by the model

Stays put
54%
Designated
18%
Optioned
26%
Traded
<1%
Released or non-tendered
1%

Pushing the cut risk up: this season's WAR (-0.07) raises it, last season's WAR (-0.09) raises it, club's run differential (-169) raises it.

Context the model does not weigh: ZiPS projects 0.1 WAR, -0.1 WAR this season; 14 RP on the 40-man, of whom Jordan Romano is headed to free agency.

Trained on every 40-man roster snapshot since 2011 and what happened in the following 90 days; it sees roster status, options, service, history and last season's line, not this season's performance or the club's intentions. How well it does.

Is there a job for him next year?

COL returns 12 RP on the 40-man once 1 free agent leaves; about 9 RP jobs survive a normal winter. By his own recent record he ranks 10th among the returners (-0.3 WAR against a bar of -0.2), which the calibrated model turns into 79% kept through the tender deadline. Ranked by ZiPS and Steamer instead, which credit his longer track record, he is 10th (0.0 WAR, bar 0.1), worth 87% kept on the same model.

By recent record: returning RPProj. WAR
1. Brennan Bernardino1.2
2. Mark Manfredi0.7
3. Juan M. Mejia0.6
4. Jimmy Herget0.5
5. Jaden Hill0.5
6. Welinton Herrera0.1
7. Nick Frasso0.1
8. Hayden Harris-0.1
9. Zach Agnoslast job-0.2
10. Blas Castano-0.3
11. T.J. Shook-0.4
12. Jeff Criswell-0.6
By ZiPS / Steamer: returning RPProj. WAR
1. Jaden Hill0.3
2. Jeff Criswell0.2
3. Jimmy Herget0.2
4. Juan M. Mejia0.2
5. Welinton Herrera0.2
6. Brennan Bernardino0.2
7. T.J. Shook0.1
8. Hayden Harris0.1
9. Nick Frassolast job0.1
10. Blas Castano0.0
11. Mark Manfredi-0.2
12. Zach Agnos-0.2

Departing free agents are excluded; players on club, mutual or player options are counted as returning. The kept probability is calibrated on every September since 2012 using the recent-record projection; the ZiPS/Steamer reading uses the same model with a different ranking, so treat it as a second opinion rather than a calibrated number. Salary enters once arbitration projections publish in October.

October: Post-season eligible

On the 40-man before noon ET Sep 1. He stays eligible as long as he remains on the 40-man or 60-day IL through the post-season; an outright after the cutoff would end automatic eligibility.

The post-season eligibility list is fixed at noon ET on September 1: everyone on the 40-man, the 60-day IL or the military list at that moment, who then stays there without interruption. Attachment 25 (Major League Rule 40)

What happens if the club…

option him to the minors
Yes, 2 option years left. 1 of the five optional assignments for 2026 remain. A 2026 option year is already used (72 days), so further trips this season cost nothing extra. Once down he must stay 15 days unless he replaces an injured or traded player.
Option years and the 20-day rule · Five optional assignments per season · Minimum stay on option
designate him for assignment (or put him on outright waivers)
The club has 7 days to trade him, pass him through outright waivers, or release him; he is paid at the major-league rate and keeps accruing service in the meantime. On outright waivers any club can claim him for $50,000, worst record first, and the claiming club takes his contract. If he clears, the club can outright him to the minors and he has no say; he stays under club control on a minor-league deal. He would then be Rule 5-eligible and would hold XX-D rights against any future outright. Post-season: an outright after the September 1 cutoff ends his automatic eligibility. He could only return as an approved injury replacement, and only if he accepts the outright and stays on a minor-league reserve list in the organization without interruption; a release makes him ineligible for anyone this October.
Designated for assignment: 7 days · Outright waivers · Article XX-D: the right to walk
release him
Release waivers cost a claiming club $1 but the claimant assumes the whole contract, so expensive players clear. The club owes the full unpaid balance of this season's salary, offset by whatever another club pays him this year. A released player is not post-season eligible for any club this year.
Release waivers and termination pay · Which rate a split contract pays at release
trade himBLOCKED
Not now: players on major-league contracts cannot be traded after the Aug 3 deadline until the day after the World Series.
Trade deadline · 10-and-5 rights · June 15 no-trade for free-agent signees
renew him for next year
Pre-arbitration: the club sets his 2027 salary near the minimum ($780,000 floor) and he has no leverage beyond a non-tender.
Minimum salaries · Tender deadline

What the rules say about him

Option years, season by season

SeasonDays on optionOption year usedStints
202672yesMar 11, 2026 to Apr 14, 2026 (20d, spring training)Apr 21, 2026 to Apr 26, 2026 (5d)Apr 27, 2026 to May 17, 2026 (20d)May 18, 2026 to May 21, 2026 (3d)Aug 8, 2026 to Sep 1, 2026 (24d)
2025189yesMar 7, 2025 to May 23, 2025 (66d, spring training)May 29, 2025 to Sep 29, 2025 (123d)

Transaction log

Sep 1, 2026RecalledColorado Rockies recalled RHP Blas Castaño from Albuquerque Isotopes.
Aug 8, 2026OptionedColorado Rockies optioned RHP Blas Castaño to Albuquerque Isotopes.
Aug 8, 2026Status changeColorado Rockies activated RHP Blas Castaño from the 15-day injured list.
Jun 21, 2026Status changeColorado Rockies placed RHP Blas Castaño on the 15-day injured list retroactive to June 18, 2026. Right pectoral strain.
May 21, 2026RecalledColorado Rockies recalled RHP Blas Castaño from Albuquerque Isotopes.
May 18, 2026OptionedColorado Rockies optioned RHP Blas Castaño to Albuquerque Isotopes.
May 17, 2026RecalledColorado Rockies recalled RHP Blas Castaño from Albuquerque Isotopes.
Apr 27, 2026OptionedColorado Rockies optioned RHP Blas Castaño to Albuquerque Isotopes.
Apr 26, 2026RecalledColorado Rockies recalled RHP Blas Castaño from Albuquerque Isotopes.
Apr 21, 2026Claimed off waiversColorado Rockies claimed RHP Blas Castaño off waivers from Seattle Mariners.
Apr 21, 2026OptionedColorado Rockies optioned RHP Blas Castaño to Albuquerque Isotopes.
Apr 14, 2026Designated for assignmentSeattle Mariners designated RHP Blas Castaño for assignment.
Mar 11, 2026OptionedSeattle Mariners optioned RHP Blas Castaño to Tacoma Rainiers.
Oct 21, 2025Status changeSeattle Mariners activated RHP Blas Castaño.
Sep 29, 2025RecalledSeattle Mariners recalled RHP Blas Castaño from Tacoma Rainiers.
May 29, 2025OptionedSeattle Mariners optioned RHP Blas Castaño to Tacoma Rainiers.
May 23, 2025RecalledSeattle Mariners recalled RHP Blas Castano from Tacoma Rainiers.
Mar 7, 2025OptionedSeattle Mariners optioned RHP Blas Castano to Tacoma Rainiers.
Nov 4, 2024Contract selectedSeattle Mariners selected the contract of RHP Blas Castano from Tacoma Rainiers.
Aug 11, 2023Signed as free agentSeattle Mariners signed free agent RHP Blas Castano to a minor league contract.
Jun 1, 2018Signed as free agentNew York Yankees signed free agent RHP Blas Castano to a minor league contract.

Service through 2025 per FanGraphs RosterResource; options and this-season service reconstructed from the MLB transaction log (reconstruction; FanGraphs shows 2). Rule 5 exposure deadline Nov 17, 2026.