The criticisms Trevor Siemian heard earlier this season -- that he isn't leading an effective offense -- are beginning to resurface.

Except this time, it's not coming from his fellow teammates. But from his head coach.

"Some of Trevor's decision-making yesterday wasn't as good as it's been," Gary Kubiak told reporters Monday. "Obviously, he got away with some, didn't get away with one [interception].

"He's gotta continue to improve. Seven starts under his belt; gonna be eight more big ones coming up here. He's gotta keep improving."

Siemian wasn't exactly crisp in the Broncos' win over the Chargers on Sunday. He barelt completed 50 percent of his passes (20-of-38) and threw no touchdowns, but did toss a brutal pick-six and several other would-be interceptions.

He also fumbled twice, losing one.

Gary Kubiak said Trevor Siemian's near-interceptions are teachable when they are "near" if not they cost you games. — Cameron Wolfe (@CameronWolfe) October 31, 2016

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With C.J. Anderson missing from the lineup, Denver couldn't run (57 total yards), couldn't score (2-for-6 in the red zone), and couldn't string together enough first downs (15) to give the defense an extended breather.

The defense that, for the umpteenth time, bailed the offense out of a bad outing. The defense that's growing sick of pulling Siemian's weight.

A few #Broncos defenders did admit it's hard not to get frustrated w offensive struggles at times, especially after turnover day like today. — Cameron Wolfe (@CameronWolfe) October 31, 2016

Kubiak is right in that Siemian's life is about to get more difficult before it gets easier. The Broncos are entering the stretch run of their schedule, with key AFC contests looming, including Sunday's primetime showdown in Oakland.

They're built to ground-and-pound, using the run to set up the pass. When the ground game is shut down like it was Sunday -- Kubiak used the term "non-existent" -- the pressure falls on Siemian to make things happen.

And, lately, he hasn't.