LAS VEGAS — Dan Mullen and UNLV do not have much time to determine who will lead the defense in 2026.
The NCAA transfer portal opens Jan. 2, placing the Rebels in a narrow window where the defensive coordinator decision could affect more than the structure of the defense. If Paul Guenther does not remain in the permanent coordinator role, UNLV will need to identify a replacement while simultaneously trying to retain current players and recruit defensive help from the portal.
That changes the type of hire Mullen needs to make. UNLV is not simply looking for the coach with the longest résumé or the most recognizable name. The Rebels need someone who can install quickly, establish credibility with current and prospective players and address a defense that showed both disruptive potential and vulnerability to explosive plays during the 2025 season.
Several coaches present different versions of that profile. Mike Scherer offers familiarity with UNLV and proof of what his defense can produce in Las Vegas. Tyson Summers brings experience and a history of creating turnovers without requiring a significant schematic transition. Todd Grantham provides the strongest connection to Mullen and an aggressive defensive identity, while Chris O’Leary represents a younger option with NFL and Notre Dame experience. Internally, Akeem Davis and Ricky Logo would allow the Rebels to preserve continuity rather than starting over.
The decision ultimately comes down to how much UNLV values familiarity, experience and developmental upside at a point in the calendar when all three matter.
Mike Scherer Already Has Proof at UNLV
Scherer would represent the most familiar option because UNLV has already seen what his defense can look like inside the program.
During his two seasons coordinating the Rebels’ defense, UNLV forced 50 turnovers, intercepted 34 passes and recorded 67 sacks and 171 tackles for loss. The 34 interceptions ranked second nationally during that span, while the Rebels finished among the national leaders in turnovers created and produced multiple All-America and All-Mountain West players.
That production eventually helped Scherer land another defensive coordinator opportunity at the Power Four level, but it also gives UNLV a clear point of comparison as Mullen evaluates what he wants next. Scherer understands the Mountain West, knows the challenges that come with building a roster at UNLV and would not need an extended adjustment period to understand the program.
His previous defenses were built around disruption. UNLV consistently created negative plays, attacked quarterbacks and forced turnovers, but that aggressiveness could also place additional pressure on the back end when the initial pressure did not reach the quarterback. The Rebels would have to decide whether they want to return to that style or pursue a coordinator who prioritizes limiting explosive plays more heavily.
Still, no other outside candidate would arrive with the same level of proof within UNLV’s environment. Scherer has already shown that his defense can produce at a high level in Las Vegas, which makes him a natural benchmark when evaluating the rest of the field.
Tyson Summers Brings Experience and Familiarity With Mullen
Summers offers a different type of experience. His defenses have consistently produced turnovers and strong situational results across multiple coordinator stops, including a two-year stretch at Western Kentucky in which the Hilltoppers forced 58 turnovers and scored nine defensive touchdowns.
His 2024 defense also produced one of the better pass-defense performances in its conference while remaining productive on third down and in scoring defense. That consistency gives Summers a résumé built less around one exceptional season and more around repeated defensive production.
There are also connections that could shorten the transition. Summers has coached in the Mountain West and previously worked within Mullen’s program at Florida, giving him familiarity with both the conference environment and the head coach he would be working under.
That could matter considerably with the portal opening almost immediately. A coordinator who already understands Mullen’s expectations and has experience installing defenses at multiple programs may be able to move more quickly than someone learning the staff and roster simultaneously.
Summers would not necessarily represent a dramatic stylistic change designed to generate attention around the hire. His appeal is predictability. UNLV would be bringing in a coach with coordinator experience, previous connections to Mullen and evidence that his defenses can create turnovers while remaining structurally sound.
Todd Grantham Would Reunite With Mullen
Grantham has the deepest history with Mullen among the outside candidates. The two worked together at Mississippi State and Florida, and Grantham has coordinated defenses at the SEC, Big 12 and NFL levels during a lengthy coaching career.
That relationship would eliminate many of the normal questions surrounding how a new coordinator fits with the head coach. Mullen already knows how Grantham teaches, installs and calls a defense, while Grantham understands the type of complementary football Mullen expects from his staff.
His defenses have traditionally been aggressive up front, relying on pressure packages and attacking protections rather than consistently playing conservatively. That style could give UNLV a clear identity and would likely appeal to front-seven players looking for opportunities to rush the passer.
The same aggressiveness has also produced uneven results when pressure does not arrive. Grantham’s defenses have sometimes allowed explosive plays when opponents successfully identify or protect against the pressure, creating a risk-reward profile that UNLV would have to consider carefully after its own issues preventing big plays.
Hiring Grantham would therefore represent more than bringing back one of Mullen’s longtime assistants. It would signal that UNLV wants to build the defense around pressure and experience while trusting the existing relationship between head coach and coordinator to accelerate the transition.
Chris O’Leary Offers a More Modern Developmental Profile
O’Leary would give UNLV a different type of candidate from the veteran coordinators on the list.
His background includes NFL experience with the Los Angeles Chargers, where he worked with a defense that finished among the league’s best in scoring, along with six seasons at Notre Dame. During his time with the Fighting Irish, O’Leary worked with a secondary that included Xavier Watts, who developed into a Nagurski Award winner and unanimous All-American.
O’Leary’s experience working with defensive backs and his NFL background could be especially valuable in portal recruiting. Players increasingly evaluate programs based on development opportunities as much as scheme, and a coordinator with recent professional and Notre Dame experience could offer UNLV a strong recruiting message, particularly in the secondary.
He also represents more of a projection as a long-term FBS defensive coordinator than coaches such as Grantham or Summers. His résumé contains significant position development and high-level defensive experience, but less extensive coordinator history.
That makes O’Leary an upside-oriented option. UNLV would be betting on his trajectory, teaching ability and modern coverage background rather than simply hiring someone based on years spent calling defenses.
Akeem Davis Would Preserve Secondary Continuity
UNLV could also decide that the best way to navigate a shortened offseason is to avoid a major transition altogether.
Davis already has credibility inside the program after overseeing a secondary that helped UNLV finish tied for fourth nationally in interceptions. Cameron Oliver recorded five interceptions and earned first-team All-Mountain West honors, continuing a pattern of turnover production that has followed Davis from previous coaching stops to Las Vegas.
Promoting Davis would preserve relationships with returning defensive backs and reduce the amount of terminology and structural adjustment required during the offseason. That continuity could become particularly valuable once the portal opens because UNLV would be recruiting players into a system that much of the existing roster already understands.
The question would be experience. Davis does not bring the same extensive FBS coordinator résumé as several outside candidates, so a promotion could require Mullen to surround him with veteran assistants capable of helping manage the entire structure of the defense.
His candidacy would therefore be less about making the easiest hire and more about whether UNLV believes the development and turnover production already occurring under Davis can translate to responsibility for the complete unit.
Ricky Logo Would Keep the Defensive Front at the Center of the Identity
Logo gives UNLV another internal option, but his candidacy would emphasize a different part of the defense.
His coaching background has been built around defensive-line development, run defense and maintaining productive rotations in the front. UNLV received sacks from 10 different defensive linemen during the season, evidence that the Rebels were able to generate production without relying entirely on one pass rusher.
That type of depth is important for a defense that wants to control early downs and prevent opponents from dictating games through the running game. Keeping Logo in a larger role could also help retain players who have already developed within his position room and understand his expectations.
The challenge would be determining how the rest of the defensive structure is organized around him. Logo’s expertise is concentrated in the front, so promoting him could require a more collaborative coordinator model with strong secondary and coverage voices elsewhere on the staff.
For UNLV, that could still work if Mullen values continuity and believes the defense should continue being built from the line of scrimmage outward.
The Calendar Makes the Decision More Important
Each option would take UNLV in a slightly different direction, but the immediate pressure comes from the calendar rather than the scheme.
The portal opens Jan. 2, and defensive players evaluating UNLV will want to understand who is coaching them, what system they are entering and how their role fits within it. The same questions apply to players already on the roster who may be evaluating whether to remain with the program.
That makes speed important, but it should not force UNLV into making a decision based entirely on familiarity. The Rebels still need a coordinator capable of addressing the problems that appeared during the season, particularly when opponents generated explosive plays or forced UNLV’s defense to defend extended possessions.
Scherer would give UNLV a coordinator who has already succeeded in the program. Summers provides experience and a connection to Mullen without requiring the same aggressive profile as some alternatives. Grantham offers the deepest relationship with Mullen and an established pressure-based identity. O’Leary brings NFL credibility and a strong developmental background in the secondary, while Davis and Logo would allow the Rebels to build from the staff and relationships already in place.
UNLV does not need every answer about its 2026 defense before the portal opens. It does need enough clarity to explain what players are being asked to join.
The Rebels spent much of the previous offseason rebuilding a roster at remarkable speed. This time, the challenge is different. Mullen has an established program, returning players to retain and another portal class to construct around them.
Whoever coordinates the defense will have a significant role in determining how successfully UNLV handles all three.