PITTSBURGH — Landry Jones had his first regular-season NFL action last week.

Now, it looks as if he will make his first start this week.

Coach Mike Tomlin said Tuesday that his team will prepare for Sunday’s game against the Chiefs at Kansas City as if Jones will be the starting quarterback.

Starter Ben Roethlisberger has been out since spraining the medical collateral ligament in his left knee Sept. 27 in a win over the Rams at St. Louis.

Backup Mike Vick suffered a strained right hamstring in last Sunday’s 25-13 victory over Arizona.

“I think it’s prudent and appropriate right now to operate under the assumption that Landry is our quarterback this week,” Tomlin said. “He is the guy that’s healthy.”

Jones had been the third-string quarterback since being drafted in the fourth round in 2013. He played well against the Cardinals, completing 8 of 12 passes for 168 yards and two touchdowns.

“We were not shocked by his performance, but we were pleased by it,” Tomlin said.

The Steelers (4-2) have gone 2-1 without Roethlisberger. However, Vick has struggled, completing 40 of 66 passes for 371 yards with two touchdowns and one interception.

Offensive coordinator Todd Haley called more low-risk plays for Vick, who signed as a free agent at the end of the preseason when backup quarterback Bruce Gradkowski was placed on injured reserve with a hand injury.

The Steelers, though, will likely open up the offense more if Jones starts. He had extensive action in the preseason as played five games rather than the normal four because of the Steelers appearance in the Hall of Fame game.

“He took advantage of those reps, like we all talked about during the course of the preseason, but regular season is different from preseason,” Tomlin said.

“It’s not what you know, it’s about what you’re capable of executing.”

While injuries have left Jones as the only healthy quarterback on the roster, Tomlin said the Steelers have not worked out any free agents. They could promote rookie wide receiver Tyler Murphy from the practice squad as he played quarterback at Boston College.