Castle is a big back in his own right. Indianapolis listed Castle at 5-11, 221 pounds in its release.
The Duke product has an interesting profile as a college back. Castle spent five years at Appalachian State without carrying the ball more than 53 times in any season, then transferred to Duke for his year of graduate eligibility and carried 115 times for 488 yards and 12 touchdowns, while also catching 17 passes for 111 yards.
Arkansas defensive tackle Cam Ball tries to make a tackle during the Razorbacks' loss to Texas A&M earlier this season.
(Arkansas Athletics)
Wisconsin safety Austin Brown (9) tackles Nebraska running back Emmett Johnson (21 during the first quarter of their game Saturday, November 18, 2023 at Camp Randall Stadium in Madison, Wisconsin.
Mark Hoffman/Milwaukee Journal Sentinel
(Mark Hoffman/Milwaukee Journal Sentinel, Mark Hoffman/Milwaukee Journal Sentinel / USA TODAY NETWORK)
GLENDALE, ARIZONA - JANUARY 08: Tahj Chambers #26 of the Ole Miss Rebels tackles Charmar Brown #6 of the Miami Hurricanes in the first quarter during the 2025 College Football Playoff Semifinal at the VRBO Fiesta Bowl at State Farm Stadium on January 08, 2026 in Glendale, Arizona. (Photo by Norm Hall/Getty Images)
(Norm Hall, Getty Images)
Nov 29, 2025; Durham, North Carolina, USA; Duke Blue Devils wide receiver Sahmir Hagans (2) runs the ball against Wake Forest Demon Deacons linebacker Whittman Whaley (40) during the fourth quarter at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images
(Zachary Taft, Zachary Taft-Imagn Images)
Aug 30, 2025; West Lafayette, Indiana, USA; Purdue Boilermakers wide receiver EJ Horton Jr. (13) runs the ball past Ball State Cardinals linebacker DeJuan Echoles Jr. (31) during the second half at Ross-Ade Stadium. Mandatory Credit: Marc Lebryk-Imagn Images
(Marc Lebryk, Marc Lebryk-Imagn Images)
Oct 25, 2025; Chapel Hill, North Carolina, USA; North Carolina Tar Heels quarterback Gio Lopez (7) passes the ball as Virginia Cavaliers defensive end Mitchell Melton (17) pressures in the third quarter at Kenan Stadium. Mandatory Credit: Bob Donnan-Imagn Images
(Bob Donnan, Bob Donnan-Imagn Images)
Collierville's Keyshawn Williams (22) chases after Houston's Lincoln Pare (4) as he rushes the ball down the sideline Thursday, Oct. 10, 2019, during a game at Collierville High School. Houston defeated Collierville 56-28.
(Max Gersh / The Commercial Appeal)
Dec 31, 2024; Glendale, AZ, USA; Penn State Nittany Lions offensive lineman Nolan Rucci (72) against the Boise State Broncos during the Fiesta Bowl at State Farm Stadium. Mandatory Credit: Mark J. Rebilas-Imagn Images
(Mark J. Rebilas, Mark J. Rebilas-Imagn Images)
Nov 15, 2025; Baton Rouge, Louisiana, USA; Arkansas Razorbacks wide receiver Raylen Sharpe (6) runs against LSU Tigers defensive back A.J. Haulcy (13) and linebacker Harold Perkins Jr. (7) during the second half at Tiger Stadium. Mandatory Credit: Stephen Lew-Imagn Images
(Stephen Lew, Stephen Lew-Imagn Images)
Dec 19, 2025; Norman, OK, USA; Alabama Crimson Tide offensive lineman Geno VanDeMark (56) against the Oklahoma Sooners during the CFP National Playoff First Round at Gaylord Family Oklahoma Memorial Stadium. Mandatory Credit: Mark J. Rebilas-Imagn Images
(Mark J. Rebilas, Mark J. Rebilas-Imagn Images)
ACU running back Jordon Vaughn slips past his teammate, wide receiver J.J. Henry who blocks SFA defensive back Kameron Reddic from making a tackle Saturday Sept. 6, 2025. Abilene Christian University defeated Stephen F. Austin University at home, 28-20.
(Ronald W. Erdrich/Reporter-News)
Aug 30, 2025; Clemson, South Carolina, USA; LSU Tigers cornerback Mansoor Delane (4) celebrates with linebacker West Weeks (33) and cornerback PJ Woodland (11) after a play against the Clemson Tigers during the second half at Memorial Stadium. Mandatory Credit: Ken Ruinard-USA TODAY Network via Imagn Images
(Ken Ruinard, Ken Ruinard-USA TODAY Network via Imagn Images)
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Arkansas defensive tackle Cam Ball tries to make a tackle during the Razorbacks' loss to Texas A&M earlier this season.
(Arkansas Athletics)
1/12
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Arkansas defensive tackle Cam Ball tries to make a tackle during the Razorbacks' loss to Texas A&M earlier this season.
(Arkansas Athletics)
2/12
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Wisconsin safety Austin Brown (9) tackles Nebraska running back Emmett Johnson (21 during the first quarter of their game Saturday, November 18, 2023 at Camp Randall Stadium in Madison, Wisconsin.
Mark Hoffman/Milwaukee Journal Sentinel
(Mark Hoffman/Milwaukee Journal Sentinel, Mark Hoffman/Milwaukee Journal Sentinel / USA TODAY NETWORK)
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GLENDALE, ARIZONA - JANUARY 08: Tahj Chambers #26 of the Ole Miss Rebels tackles Charmar Brown #6 of the Miami Hurricanes in the first quarter during the 2025 College Football Playoff Semifinal at the VRBO Fiesta Bowl at State Farm Stadium on January 08, 2026 in Glendale, Arizona. (Photo by Norm Hall/Getty Images)
(Norm Hall, Getty Images)
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Nov 29, 2025; Durham, North Carolina, USA; Duke Blue Devils wide receiver Sahmir Hagans (2) runs the ball against Wake Forest Demon Deacons linebacker Whittman Whaley (40) during the fourth quarter at Wallace Wade Stadium. Mandatory Credit: Zachary Taft-Imagn Images
(Zachary Taft, Zachary Taft-Imagn Images)
5/12
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Aug 30, 2025; West Lafayette, Indiana, USA; Purdue Boilermakers wide receiver EJ Horton Jr. (13) runs the ball past Ball State Cardinals linebacker DeJuan Echoles Jr. (31) during the second half at Ross-Ade Stadium. Mandatory Credit: Marc Lebryk-Imagn Images
(Marc Lebryk, Marc Lebryk-Imagn Images)
6/12
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Oct 25, 2025; Chapel Hill, North Carolina, USA; North Carolina Tar Heels quarterback Gio Lopez (7) passes the ball as Virginia Cavaliers defensive end Mitchell Melton (17) pressures in the third quarter at Kenan Stadium. Mandatory Credit: Bob Donnan-Imagn Images
(Bob Donnan, Bob Donnan-Imagn Images)
7/12
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Collierville's Keyshawn Williams (22) chases after Houston's Lincoln Pare (4) as he rushes the ball down the sideline Thursday, Oct. 10, 2019, during a game at Collierville High School. Houston defeated Collierville 56-28.
(Max Gersh / The Commercial Appeal)
8/12
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Dec 31, 2024; Glendale, AZ, USA; Penn State Nittany Lions offensive lineman Nolan Rucci (72) against the Boise State Broncos during the Fiesta Bowl at State Farm Stadium. Mandatory Credit: Mark J. Rebilas-Imagn Images
(Mark J. Rebilas, Mark J. Rebilas-Imagn Images)
9/12
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Nov 15, 2025; Baton Rouge, Louisiana, USA; Arkansas Razorbacks wide receiver Raylen Sharpe (6) runs against LSU Tigers defensive back A.J. Haulcy (13) and linebacker Harold Perkins Jr. (7) during the second half at Tiger Stadium. Mandatory Credit: Stephen Lew-Imagn Images
(Stephen Lew, Stephen Lew-Imagn Images)
10/12
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Dec 19, 2025; Norman, OK, USA; Alabama Crimson Tide offensive lineman Geno VanDeMark (56) against the Oklahoma Sooners during the CFP National Playoff First Round at Gaylord Family Oklahoma Memorial Stadium. Mandatory Credit: Mark J. Rebilas-Imagn Images
(Mark J. Rebilas, Mark J. Rebilas-Imagn Images)
11/12
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ACU running back Jordon Vaughn slips past his teammate, wide receiver J.J. Henry who blocks SFA defensive back Kameron Reddic from making a tackle Saturday Sept. 6, 2025. Abilene Christian University defeated Stephen F. Austin University at home, 28-20.
(Ronald W. Erdrich/Reporter-News)
12/12
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Aug 30, 2025; Clemson, South Carolina, USA; LSU Tigers cornerback Mansoor Delane (4) celebrates with linebacker West Weeks (33) and cornerback PJ Woodland (11) after a play against the Clemson Tigers during the second half at Memorial Stadium. Mandatory Credit: Ken Ruinard-USA TODAY Network via Imagn Images
(Ken Ruinard, Ken Ruinard-USA TODAY Network via Imagn Images)
Duke used Castle as a short-yardage back, a similar role to what theColtslikely envisioned for the 6-3, 230-pound Vaughn and also the team’s seventh-round pick, former Kentucky running back Seth McGowan.
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Castle joins Texas State running back Lincoln Pare as undrafted rookies on the Indianapolis roster, long shots to make the 53-man roster behindJonathan Taylor, 2025 fifth-rounderDJ Giddensand McGowan.