ENGLEWOOD, Colo. -- Thirteen games into Case Keenum’s first season with the Denver Broncos, he finds himself at a crossroad in a job he has always wanted and cleared plenty of vocational hurdles to get.

Keenum, who was signed to a "prove-it" two-year contract in March, is now at the point where the directive to not make too many mistakes intersects with his bosses' desire for more big plays. Because while Broncos coach Vance Joseph has said Keenum “has played his best football the last month," that quality has come with a price, especially in a potentially crushing loss to the San Francisco 49ers on Sunday.

“[On Sunday], he was a little cautious with the ball," Joseph said this week. “The bottom line: We’ve got three weeks to play, he’s got to make more plays, and sometimes taking some chances allows you to make more plays. There are going to be turnovers, so he can’t worry about that. You can’t play this game perfect, but I want Case to be more aggressive … He’s got to be aggressive down the seams and not worry about making mistakes."

OK, point taken. The Broncos are 3-1 in their past four games, but Keenum has thrown for fewer than 200 yards in three of those games and threw for 205 yards in the fourth. But after throwing 10 interceptions in the first eight games -- he had the league lead at one point in the first half -- Keenum has not thrown a pick in the past five games.

But the Broncos aren't exactly built for air travel on offense right now, given that they traded wide receiver Demaryius Thomas on Oct. 30 and wide receiver Emmanuel Sanders went to injured reserve with a ruptured Achilles last week, just days before the loss in San Francisco. The Broncos now essentially have three rookies -- two picks from the 2018 draft (Courtland Sutton and DaeSean Hamilton) and Tim Patrick, who spent much of his rookie season in 2017 on the Broncos' practice squad -- as their top three wide receivers, their top two tight ends are on injured reserve, and they have three starting offensive linemen on injured reserve.

The Broncos and Keenum have to find a way to blend some of the big plays he had in the first half -- Keenum had 33 completions of 20 or more yards and eight of more than 40 yards in the first eight games -- while eliminating the turnovers that negated the impact of some of those big plays. In the past five games, including Sunday’s loss, the Broncos have 12 completions of at least 20 yards and one of more than 40 yards.

“We’re at that point in the season where we’ve got to make plays, and we’ve got to score points," Keenum said. “… I’ve said that before, and I can’t get caught back there with the ball in my hands. I’ve got to give guys chances down the field. It looks different on different plays, but in general, that’s a good mindset to have. I think being smart with the ball, continuing to be smart with the ball, but giving guys chances when we feel like it’s a good matchup or advantageous time to take a shot or take a chance down the field."

Some opposing defensive coaches say the Broncos ran the ball more consistently early in the season, especially on early downs, so Keenum found more room to use play-action passing for deeper plays. Against the 49ers -- the first game without Sanders -- the Broncos struggled to run the ball for much of the day (102 yards on 27 carries) and their past two losses are the only games in the season’s second half in which the Broncos haven’t averaged more than 3.8 yards per carry.

For his part, Keenum said he wants to be the guy to fix it, to push the Broncos’ offense into high gear.

“My entire life, I’ve absolutely loved having the ball in my hands, making decisions and really being a big part of why my team wins," Keenum said. "That’s what I want to be. I want to win. I’m a winner, I’m competitive to a fault, and I think that’s part of what drives me and makes me who I am. I take it on myself that I’ve got to do better. I’ve got to play better, I’ve got to give my guys chances down the field, and that’s it."