ENGLEWOOD, Colo. (AP) — When the Denver Broncos signed Case Keenum to a two-year, $36 million deal last spring, they figured they were getting the quarterback who had led the Vikings to within one step of the Super Bowl.

Instead, they've gotten the journeyman he was with the Texans and Rams.

At least so far.

Keenum's eight interceptions are tied for the league lead and are one more than he threw in 15 games last year. He's been especially turnover-prone in the red zone and he's the only quarterback in the NFL who has thrown an interception in all six of his team's games so far.

Keenum's 15 sacks put him on pace for 40, nearly double what he had last season or in 2016 when he served as Jared Goff's tutor in Los Angeles.

Last week, Broncos general manager John Elway gave Keenum a vote of confidence, saying on Orange & Blue 760, "I think that Case has done a nice job. It's always an adjustment getting used to a new offense and a new coaching staff and what he's used to. He's provided leadership, he's provided that grit."

Then, Elway hit the scouting trail, flying to Eugene, Oregon, with top personnel assistant Matt Russell to check out Ducks QB Justin Herbert, who is expected to be the top quarterback in the 2019 NFL draft if he leaves school after this season.

Keenum acknowledged Tuesday that his adjustment has been a rocky one.

"It's tough," Keenum said. "You look at guys that have been in offenses for two, three, four, 10 years. The guy who played last night (Packers star Aaron Rodgers) has been in that offense a while and you start to know it like the back of your hand. You have just seen so many different plays and so many defenses you know what tends to get open."

On the other hand, this is his "first time throwing with these guys," said Keenum, quickly adding, "These are definitely not excuses. I'm not sitting here making excuses, but I think we're getting better. That's the goal, and it takes time."

The Broncos (2-4) have lost four straight heading into their game Thursday night at Arizona (1-5).

They hung tough in two of those losses, both at home, against two of the league's top teams.

They lost 27-23 to the Chiefs (5-1) in a game in which Keenum missed a wide open Demaryius Thomas for the potential game-winning score in the closing seconds, and the Rams beat them 23-20 Sunday thanks to penalties and an interception that cost the Broncos at least 10 points, including one on Emmanuel Sanders for taunting after what he mistakenly thought was a 44-yard touchdown.

Last week, offensive coordinator Bill Musgrave bunched his receivers closer to struggling left tackle Garett Bolles at times and used more two-back sets. Still, he didn't call many more runs for rookie running backs Phillip Lindsay and Royce Freeman, who have combined for four TD runs and a 5.19-yard average per carry despite the imbalance in play calls.

The Broncos rushed just 17 times and threw 41 passes against L.A. During their skid, they've run 80 times and thrown 159 passes.

"When you're playing (from) behind, you're trying to stick to your game plan and keep running the ball here and there," Keenum said. "But especially with the later it gets, you need to make explosive plays. That gives the defense, especially the defensive line, a chance to tee off. ...

"It's tough. But we put ourselves in that position early and we've got to make sure we don't do that again this week."

Bolles, the team's first-round draft pick in 2017, continues to struggle — he leads the league with six holding calls a year after committing an NFL-high 10. And losing left guard Ronald Leary to a torn Achilles on Sunday means Max Garcia returns to the spot he occupied next to Bolles much of last season.

Bolles said Leary's injury was "a tough one for me. It made me super emotional, but I have to move on. I have to help Max as much as he helps me and we have to get the job done."

Coach Vance Joseph said Sam Jones, a rookie from Arizona State, will be the backup guard against the Cardinals.

"I trust the offensive line no matter who's in there," Keenum said.

Notes: S Su'a Cravens (knee surgery) and WR-KR Jordan Taylor (double hip surgery) both practiced for the first time this season. "It was good to see Jordan back out there and also Su'a, but it's a jog-through today," Joseph said. "We'll go fast tomorrow, as far as the 7-on-7 red zone and the team red zone, so we'll see how they feel."

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