The search has begun to replace defensive coordinator Dave Aranda, who was hired by LSU from Wisconsin for the same position on Friday.

The next coordinator to take over the Badgers' defense will have big shoes to fill, to say the least. Aranda, known as the "mad scientist" among his players, revamped an already respectable group for the 2013 season when he came over from Utah State with Gary Andersen. He implemented his 3-4 scheme from the Aggies, and the players bought in.

Heading into the 2015 Holiday Bowl, Aranda's defenses allowed an average of 16.9 points per game since that 2013 season, second-best in the nation behind Alabama. In that span, the Badgers have also allowed only 289.4 yards per game, which leads the nation. This season alone, Wisconsin gave up just 13.7 points per game -- again second-best in behind Alabama -- and only 268.5 yards per game, third in the nation.

While the search is still obviously very young, here are some names that could be thrown around as Aranda's replacement. Take note: this is more thinking outloud than any reporting. We'll follow up as we hear more.

Todd Orlando

He's the hot name being tossed around early on, and he has Wisconsin ties. A former Badgers linebacker who played under Barry Alvarez from 1990-94, Orlando actually took over for Aranda at Utah State from 2013-14 and had success.

In Orlando's two seasons as Utah State's defensive coordinator, the Aggies ranked 12th nationally in 2014 at 19.7 points per game and seventh nationally in 2013 at 17.1. His squads forced 59 turnovers over the two seasons, including 30 in 2014 (10th-best in the FBS).

He jumped on Houston's coaching staff for the 2015 season and in his only season as the Cougars' defensive coordinator, his defense ranked 53rd in total defense (383.6 yards per game) and eighth in rush defense by allowing only 108.9 yards per contest. Houston also surrendered 20.7 points per game, 20th in the nation.

In the Cougars' 38-24 win over Florida State in the Chick-Fil-A Peach Bowl earlier this week, Seminoles running back Dalvin Cook was held to 33 yards on 16 carries, while Houston's defense forced five turnovers (four interceptions).

This Houston defense that is shutting down FSU is coordinated by Todd Orlando, who played for the #Badgers and is tight with Joe Rudolph. — Jim Polzin (@JimPolzinWSJ) December 31, 2015

A 20-year coaching veteran, he runs a 3-4 scheme, which bodes well for the personnel already at Wisconsin. The only questions are if he'd be interested in returning to Madison, and what the price tag would be (and would Houston open up its pocket books like it did for head coach Tom Herman?)

Coaching experience

2015-: Houston, Defensive coordinator/linebackers

2013-14: Utah State, Defensive coordinator/safeties

2011-12: Florida International, Defensive coordinator/inside linebackers

2005-10: UConn, Defensive coordinator/Iinside linebackers

1999-2004: UConn, Inside linebackers

1996-98: Pennsylvania, Linebackers

1995: Fox Chapel Area (Pa.) HS, Defensive coordinator

1994: Central Catholic (Pa.) HS, Defensive coordinator

Tim Tibesar

Currently the outside linebackers coach at Wisconsin, BadgerBlitz.com's Jon McNamara and John Veldhuis both, along with FootballScoop.com, noted the former defensive coordinator and NFL linebackers coach could be the in-house choice, and a good one.

He has Big Ten experience, working as a defensive consultant at Northwestern in 2014 and the defensive coordinator at Purdue in 2012, when the Boilermakers led the Big Ten in interceptions, forced fumbles and takeaways. On top of that, he's also worked as defensive coordinator at Kansas State for two seasons from 2007-08 and North Dakota from 2004-05.

Tibesar also can sell his time in the NFL and CFL. In 2013, he was the linebackers coach for the Chicago Bears after helping the Montreal Alouettes win back-to-back Grey Cup championships as linebackers coach from 2009-10 and defensive coordinator in 2011.

The veteran assistant can be credited with helping outside linebackers Joe Schobert and Vince Biegel become one of the best duos in the nation, as they tallied 33.5 tackles for loss and 17.5 sacks this season. Converted tight end T.J. Watt developed quickly under the tutelage of Tibesar, who saw his playing time increase through the season in various subpackages.

One wonders if Wisconsin would look from within to hire, or bring in someone from the outside. Also, as Fox Sports Wisconsin's Dave Heller tweeted on Saturday, some of the statistics with his time at Purdue or Kansas State weren't so hot.

Coaching experience

2014: Northwestern, Defensive consultant

2013: Chicago Bears, Linebackers

2012: Purdue, Defensive coordinator/linebackers

2011: Montreal Alouettes, Defensive coordinator

2009-10: Montreal Alouettes, Linebackers

2007-08: Kansas State, Defensive coordinator

2004-05: North Dakota, Defensive coordinator

Mel Tucker

Because he's a former UW player, Tucker's name should come up in discussion. The former defensive back under Alvarez reportedly met with UW officials back in 2012 after Bret Bielema left for Arkansas.

Tucker had a disastrous run as the Bears' defensive coordinator from 2012-13, but he's helped Nick Saban and Alabama reach the College Football Playoff national championship game as an assistant head coach and defensive backs coach this season in Tuscaloosa. The Crimson Tide are No. 2 in the nation in total defense (256.8 yards per game, just ahead of Wisconsin), No. 1 in rush defense (70.8 yards per game) and No. 18 against the pass (allowing under 186 yards per game in the SEC).

Alabama appears to have run a 3-4 defense, but would Tucker want to come back to Wisconsin? If you search his name on Twitter, there's discussion of Tucker heading with former Alabama defensive coordinator Kirby Smart to Georgia.

Coaching experience

2015: Alabama, Assistant head coach/defensive backs

2013-14: Chicago Bears, Defensive coordinator

2012: Jacksonville Jaguars, Assistant head coach/defensive coordinator

2011: Jacksonville Jaguars, Interim head coach

2009-11: Jacksonville Jaguars, Defensive coordinator

2008: Cleveland Browns, Defensive coordinator

2005-07: Cleveland Browns, Defensive backs

2004: Ohio State, Co-defensive coordinator

2001-03: Ohio State, Defensive backs

2000: LSU, Defensive backs

1999: Miami (Ohio), Defensive backs

1997-98: Michigan State, Graduate assistant