More than a month into preseason practices, the Vikings’ starting safety spot alongside Husain Abdullah is still undecided.

Tyrell Johnson and Jamarca Sanford have alternated first-team reps for most of camp, with Sanford starting Saturday against the Cowboys. The staff has not committed to a starter for Thursday’s preseason game against the Texans.

Defensive coordinator Fred Pagac doesn’t seem to have a problem with either player creating separation for the job because the effort is there.

“I’m telling you, both kids have worked their butts off this year,” Pagac said. “They’re doing a good job right now. I’m happy with both of them right now, and we’ll continue to see what happens.”

Sanford made a standout play on defense Tuesday, intercepting a Christian Ponder pass on a slant route. Johnson scooped up a difficult onside kick bounce in special-teams drills.

A decision on the starter will come after the Texans game, Pagac said. Rookie safety Mistral Raymond is battling for a spot on the 53-man roster.

Quite the workload: Defensive end Everson Griffen, who is practicing at linebacker this wee k, will split reps between the positions Thursday.

Pagac said Griffen’s talent can be used on two platforms.

“Before it’s all said and done, he’s going to be a good defensive end,” Pagac said. “He might end up being a heck of a linebacker, too, and we just wanted to check his movement from behind the ball.”

The 6-foot-3, 273-pound Griffen entered camp as Jared Allen’s backup and has played well at defensive end. But the Vikings want to expand the role of rookie Christian Ballard, who can play tackle and end, while using Griffen’s athleticism elsewhere.

QB, RB rotations: Ponder starting Thursday is “another step in the process” but won’t solely determine the No. 2 quarterback job, offensive coordinator Bill Musgrave said.

Ponder and Joe Webb have alternated the order of reps behind starter Donovan McNabb, who will not play Thursday.

“It’s not a make-or-break for anybody,” Musgrave said. “It’s just another chance for those guys to grow and develop and show some improvement, we hope.”

Ponder and Webb executed the two-minute drill in Tuesday’s practice, the last workout before the Texans game.

The Vikings will increase the reps of running backs Alex Robinson and Tristan Davis on Thursday as the team rests Adrian Peterson, Toby Gerhart and injured Lorenzo Booker (back).

Recently signed Caleb King will enter the game “on a limited basis,” Musgrave said.