ALAMEDA — Pro Bowl left tackle Donald Penn missed practice for the third straight day with a left knee injury and his status for the Raiders’ Wild Card playoff game Saturday is in doubt.

“He didn’t go again today,” Raiders coach Jack Del Rio said Thursday before the team boarded buses headed for the airport and a charter flight to Houston. “So we’ll see how he finishes the week.”

There is precious little time left in the week, given there will be a single walk-through practice in Houston Friday.

Penn was injured after being pushed over backward by Kyke Peko. He left and later returned for a single play. Struggling to stand his ground, Penn was shoved into quarterback Connor Cook by Denver linebacker Von Miller.

Penn ended up missing six snaps, and during that time right tackle Menelik Watson played left tackle with Vadal Alexander playing on the right side.

Judging from the way the Raiders were lining up during the media window, Watson is the likely starter on the left side if Penn can’t play, with Austin Howard on the right side.

“Definitely some mixing and matching going on,” offensive coordinator Bill Musgrave said. “This time of year, a lot of people are banged up. We’ll put our healthiest five bodies out there and put them in a good place where they can work cohesively and get a good end result.”

Watson won his starting job back for the Week 16 game against Indianapolis on the right side after fighting through calf and groin injuries. Howard started 10 games this season, but was inactive against the Colts and Broncos because he isn’t utilized as an extra tight end in heavy formations.

“You know what, the coaches have plans,” Howard said. “You know, we’ll see what happens. They make sure that we’re all prepared. Fortunately, I feel that we have a lot of depth on this O-line. We have guys that can and want to play, so we’ll get it taken care of.”

Other options include moving left guard Kelechi Osemele to left tackle, something the Raiders did briefly in Week 1, and playing Jon Feliciano or Vadal Alexander at left guard while leaving Watson at right tackle.

Other Raiders who did not participate in practice Thursday were quarterback Derek Carr (ankle) and safety Nate Allen (concussion). Quarterback Matt McGloin appeared to be throwing without pain during warm-ups and drills and was listed as limited, with the hope being he will be available to back up Cook.