Ahead of a preseason shortened from four exhibitions to three in the new 17-game regular-season format, Vikings coach Mike Zimmer said he's still trying to decide how much his starters will play.

This week's joint practices with the Broncos, scheduled for Wednesday and Thursday afternoon before Saturday's preseason opener at U.S. Bank Stadium, will help coaches evaluate starters in lieu of a fourth preseason game. Zimmer said the Vikings might treat the second game, Aug. 21 against Indianapolis, like they used to treat the third "dress rehearsal" game when starters played the first half.

"I've thought about it a lot," Zimmer said. "I was talking to [safety] Harrison Smith about it some the other day, about trying to get some tackling in [at practices] and things like that. I do know that these guys, they need to get a little bit of action while they're getting ready to go.

"I anticipate that they'll play [in] the second game a pretty good amount, then we'll see where we're at for the third game."

The third exhibition, Aug. 27 in Kansas City, comes four days before all NFL teams must trim rosters down to 53 players for the regular season. Because it's the last preseason game, Vikings coaches might treat it like they previously did the fourth game where starters rested, and backups competed for roster spots.

"We had some bubble guys who made the team because of how they performed in that [final] game," Zimmer said.

Barr returns, Jefferson sidelined

Linebacker Anthony Barr returned to practice Monday after a couple days off for rest and recovery. Zimmer said he told Barr not to attend Saturday's practice at U.S. Bank Stadium.

Receiver Justin Jefferson (shoulder) and defensive tackle Sheldon Richardson were the only players not in pads at the start of practice. Receiver Dede Westbrook (knee) and left tackle Christian Darrisaw (groin) remain limited and held out of 11-on-11 drills.

Jefferson, whom Zimmer said should return "pretty quick" from Friday's shoulder injury, caught passes at or below shoulder height during warmups.

Cornerback Kris Boyd left practice with a trainer and did not return.

Assistant head coach Andre Patterson and his son, AC Patterson, an offensive quality control coach, were away from the team Monday to attend the funeral for Andre Patterson's mother. Assistant line coach Imarjaye Albury and senior defensive assistant Paul Guenther worked with the defensive linemen.

"Our thoughts are with Andre Patterson and AC," Zimmer said.

Hill is 'new' left tackle

Rashod Hill has long been an emergency option for the Vikings offensive line. He's been the top left tackle throughout this training camp because Darrisaw has yet to take a snap in team drills while recovering from a nagging groin injury.

Despite other offers in free agency this spring, Hill re-signed in Minnesota on a one-year deal worth nearly $2.4 million because of the coaching staff. Now Hill enters his sixth Vikings season with some tips in his back pocket from a couple months of training with Saints Pro Bowl left tackle Terron Armstead.

"He showed me a lot of stuff," Hill said. "Me, him, [Jaguars tackle] Cam Robinson, a couple guys like that. [former Packers and Lions guard T.J.] Lang was down for a little bit. We got a group of guys down there in Dallas and we feed off each other. We'll bring up film from previous seasons. They show me what I need to do, little stuff I can work on."

Vikings add receiver

The Vikings signed rookie receiver Warren Jackson on Monday, providing depth to a position hampered because of injuries to Jefferson and Olabisi Johnson (knee). Jackson, listed at 6-6 and 219 pounds, was an undrafted signing by the Broncos before he was released last week. Jackson opted out of his final year at Colorado State last fall.