FAYETTEVILLE, Ark. (AP) -- Bret Bielema stressed throughout the preseason the importance of having backups ready at all positions.
The first-year Arkansas coach had that belief put the test in a big way on Saturday when starting quarterback Brandon Allen injured his shoulder on a first-quarter touchdown run. Allen didn't return following the play, but the Razorbacks didn't need him.
Alex Collins and Jonathan Williams made sure of that, combining to rush for 231 yards and a pair of touchdowns as Arkansas (3-0) pulled away in the second half for a 24-3 win over Southern Mississippi.
Bielema said after the game that Allen, who took over as the starter this season for Tyler Wilson, bruised his right shoulder while diving on his 5-yard touchdown run.
The sophomore was replaced by AJ Derby and spent the second half on the Razorbacks sideline, wearing street clothes and with his upper arm tightly held against his body in a sling, but Bielema said Allen is ''pretty convinced'' he'll play next week at Rutgers.
''We couldn't ask for (Derby) to handle that second half any better,'' Bielema said. ''I thought our coaches did a nice job at halftime of getting some plays they felt comfortable with him.''
Without Allen, Arkansas had just 69 yards passing in the win - more than enough thanks to the continued rushing dominance of Collins and Williams, who entered the game first and third, respectively, in the Southeastern Conference in rushing.
Williams had 116 yards rushing on 16 carries, while Collins had 115 on 25 attempts for the Razorbacks. The Florida native became the first freshman in SEC history to top the 100-yard mark in his first three games, the first player overall since Oklahoma's Adrian Peterson in 2004.
''I'm honored about that, and I appreciate it,'' Collins said. ''But for my offensive line, I've got to give credit to them first.
''... I just appreciate everything that everyone has been doing for me.''
The loss was the 15th straight for the Golden Eagles (0-3), the longest losing streak in the country. Southern Mississippi was 0-12 last season under former coach Ellis Johnson, and it entered this week last in the country with 10 turnovers through two games under first-year coach Todd Monken.
The turnovers continued to mount on Saturday, with quarterback Allan Bridgford throwing a pair of interceptions while Arkansas was struggling to move the ball offensively in Allen's absence. Bridgford has now thrown seven interceptions this season, and he finished 17-of-33 passing for 133 yards.
The senior was under pressure throughout the game from an Arkansas defense that finished with three sacks, all by senior defensive end Chris Smith. Jalen Richard led Southern Mississippi with 94 yards rushing on 14 carries.
''I think it played out like I thought it would,'' Monken said. ''Sometimes that doesn't work out. I thought they had a good football team.
''I still believe we have a good football team.''
Arkansas trailed in the fourth quarter last week against Samford before rallying for a 31-21 win. The Razorbacks never trailed on Saturday, but they had plenty to overcome without Allen.
The sophomore, who won the starting job in the spring, threw his first interception of the season in the first quarter. However, he responded on Arkansas' next drive, scrambling for a 5-yard touchdown run on third and goal to put the Razorbacks up 7-0.
It was on that play, while diving into the end zone, that Allen injured his right shoulder.
With Allen out, Arkansas struggled initially with Derby, who spent last season in junior college after transferring from Iowa. The Razorbacks ran the ball four straight times on Derby's first drive, which ended on a punt after the junior fumbled a shotgun snap on third down.
Despite the opening, Southern Mississippi was unable to capitalize.
Derby finished 4-of-6 passing for 36 yards in an ultra-conservative effort without Allen, who was 2 of 5 for 33 yards before his injury.
''I felt good in the second half,'' Derby said. ''Our offensive line just was amazing, and the running backs did great. It took a lot of pressure off of myself.''
Arkansas didn't need the passing game in the second half - especially with Collins and Williams leading the way.
Williams put Arkansas up 17-3 with a 45-yard touchdown sprint in the third quarter, and Collins capped the scoring with a 7-yard scoring run on his own in the fourth.
It was just another week for Collins, who had 131 yard rushing in the season opener against Louisiana-Lafayette and topped that with a 172-yard effort against Samford last week.
The Razorbacks finished with 258 yards rushing - more than enough to overpower the struggling Golden Eagles on Saturday.
''We just wear some people down,'' Bielema said. ''I don't know if a lot of people want to play four quarters of football the way that we do.''