As it prepares to open Big Ten play against Penn State, the Iowa football team is making a lineup change at free safety and adjusting to an injury that will sideline its second-leading rusher for at least the next three games.

Sophomore Amani Hooker has moved in front of Jake Gervase on the depth chart at free safety for Saturday’s 6:30 p.m. game, while Toren Young and Ivory Kelly-Martin share the second-team spot at running back as James Butler begins working his way back from an elbow injury.

The move in the secondary comes after Hooker took over for Gervase after the first quarter of Saturday’s win over North Texas, a change made after Gervase was unable to get the correct angle to prevent a 41-yard touchdown run by Jeffery Wilson through the middle of the Iowa defense.

Coach Kirk Ferentz hinted following the game that a rotation at safety moving forward was a possibility and in addition to Hooker at free safety, Gervase is now listed as the back-up to strong safety Miles Taylor.

“We’ve felt good about the way Amani has been playing, so we kind of see all three guys pretty even right now,’’ Ferentz said. “We may start a three-way rotation, but we will play it by ear.’’

Iowa has no option but to move Young and Kelly-Martin up the depth chart after Butler exited Saturday’s game in the third quarter with an elbow injury. The pair combined for 152 yards in the 31-14 win.

Ferentz said during a weekly interview published Sunday evening on the university’s athletics website that Butler will likely be out through Iowa’s bye week.

That would sideline the graduate transfer who has rushed for 158 yards on 36 carries through three games for at least the next three games with hopes of him returning to action on Oct. 21 at Northwestern.

“It will be a couple of weeks before we get him back,’’ Ferentz said, adding that he expects running back Akrum Wadley and tight end Noah Fant to be good to go against the fourth-ranked Nittany Lions.

Wadley had a minor ankle injury while Fant suffered what he called “a little stinger’’ during the second half of the North Texas game. Wadley did not return to action, while Fant was back on the field after being put in a brace.

Ferentz said he believed both players “have an opportunity to be ready by midweek if not sooner.’’