FAYETTEVILLE — Bobby Petrino picked a few familiar faces and several longtime assistants to round out his first football coaching staff at Arkansas.

Petrino’s staff consists of two former Razorbacks (Tim Horton and Kirk Botkin), one veteran Arkansas assistant (Bobby Allen) and a handful of coaches who have worked with Petrino in the past (Paul Petrino, Garrick McGee and Mike Summers).

Former Mississippi State defensive coordinator Ellis Johnson was officially named Arkansas’ defensive coordinator on Friday, though his hire has been known for several days.

In fact, Petrino has had much of his staff in place for the past few days, but he filled out the remainder of it by hiring the last few positions.

Arkansas on Friday evening released the names of all the assistants on staff.

Former Louisville linebackers coach Reggie Johnson was hired to serve in the same role at Arkansas. Former Virginia Tech secondary coach Lorenzo Ward will coach the Razorbacks’ defensive backs.

And Petrino named Mark Robinson, a former football operations and coaching assistant at Texas A&M, as his director of football operations at Arkansas.

“These coaches and administrators have a wealth of experience at the highest level of collegiate athletics and in the professional ranks,” Petrino said in a statement released through the university. “I’m confident that they (will) work tirelessly as we mold our program, and that they will represent the Razorbacks in a first-class fashion.”

Petrino, who was at the Broyles Center on Friday, was unavailable for further comment. He hasn’t spoken with the local media since a Dec. 18 news conference.

Along with naming the remainder of his staff, Petrino defined the roles of several assistants who were hired last month.

Horton, who spent this past season as the running backs coach under former Arkansas coach Houston Nutt, will have an increased role for Petrino.

Horton will coach the tight ends and serve as the Razorbacks’ recruiting coordinator in addition to continuing to coach the running backs.

Meanwhile, Allen will shift from coaching Arkansas’ cornerbacks to coaching its defensive tackles. But he won’t be in charge of the entire defensive line.

Botkin, who was named to Arkansas’ All-Decade Team in the 1990s as a tight end, will coach the Razorbacks’ defensive ends.

He’ll also coach the special teams, which proved to be a particularly troubling area in Arkansas’ 38-7 loss to No. 7 Missouri in last Tuesday’s Cotton Bowl.

Allen said last week that the addition of himself and Horton will benefit the new coaching staff, especially with all the change going on next season.

“Coming into any new situation, there’s going to be questions that need to be asked and it’s always nice when there’s people that have been here. (The other coaches) can ask us,” Allen said. “That’s probably been the biggest thing, just information, being able to give them information.

“Secondly, as you get to know a new team, the players are at ease when there’s a couple of guys that they know that know their personalities.”

Allen and Horton are the only holdovers from Nutt’s previous staff. All of Petrino’s other assistants spent this past year coaching somewhere other than at Arkansas.

Paul Petrino, who was hired Dec. 15 as the Razorbacks’ offensive coordinator, was on his older brother’s staff with the Atlanta Falcons in 2007. So was Summers.

Summers served as Louisville’s offensive line coach from 2003-06, then followed Petrino to the Falcons this past year. He’ll have the task of rebuilding an offensive line that will lose at least two starters in tackle Nate Garner and guard/tackle Robert Felton.