There are all sorts of reasons the wheels came off in the fourth quarter for Cal against Miami on Saturday night.

And just as many ways the Bears could have averted letting a 25-point lead turn into a 39-38 nightmare defeat.

One more first down at some point in the fourth quarter might have taken another couple minutes off the clock and dented the Miami rally. Avoiding a catastrophic blown coverage on the Hurricanes’ 77-yard pass play on the final drive would almost certainly have changed the outcome.

And that doesn’t address what everyone seems to agree was an egregious non-call on the targeting play against Cal quarterback Fernando Mendoza late in the game.

None of it excuses squandering leads of 35-10 in the third quarter and 38-18 in the fourth, even against a talented and explosive Hurricanes’ offense.

Hidden amongst the wreckage of the night is one undeniable shortcoming: The Bears cannot run the ball.

Think about it, the coaching staff has worked for a couple years at developing a big-play offense. Mendoza had four pass completions in excess of 50 yards against Miami — something Cal hasn’t accomplished in at least a dozen seasons.

Even the prolific Bears of Jared Goff under coach Sonny Dykes never had four plays of at least 50 yards in a game, although they did have three of them against Arizona State in 2015 plus two more that went 49 yards.

Mendoza, who has passed for 588 yards in defeats the past two games, is among six ACC quarterbacks named on Monday to the Johnny Unitas Golden Arm Award Top-25 watch list.

His four big plays against Miami added up to 230 yards. On their other 45 offensive snaps, the Bears totaled just 140 yards.

The key number there was the Bears’ total plays — 49, including the four big ones. Miami ran 86 plays — 37 more snaps than Cal managed. Coach Justin Wilcox talks about that discrepancy in the video above.

The most glaring numbers are in the run game. Cal had 73 net rushing yards on 25 attempts, but those include eight rushes (or sacks) credited to Mendoza and backup QB Chandler Rogers (who played well) and a creative 20-yard end-around by wide receiver Jonathan Brady.

So what did the Cal running backs get done? Not much. Certainly not enough.

They ran the ball just 15 times and netted 23 yards. That’s 1.5 yards per attempt by the running backs. Nine of those 15 tries went for 1 yard or less. Ouch.

Preseason All-America candidate Jaydn Ott, who has been hobbled by an ankle injury, was healthy enough to score on a 66-yard screen pass play down the right sideline. And he had a 5-yard touchdown run. His other six running plays netted minus-3 yards, leaving him with a career-low 2 rushing yards.

Backup Jaivian Thomas had a 19-yard run, but totaled 1 yard on his other six rushes. 

It’s important to remember Cal was ahead on the scoreboard most of the game — way ahead for a long time. That’s when teams will run the ball to milk the clock. The Bears didn’t run it, probably because they know they can’t.

The offensive line is not the whole problem but it is part of it. Cal allowed 13 sacks the two previous games and couldn’t get its ground game going in this one against a Miami defense that gave up 206 rushing yards to Virginia Tech in its previous outing.

This actually has been an issue since the Bears’ opening game against UC Davis, when Cal’s backs carried 28 times for 88 yards — just 3.1 yards per attempt — against an FCS opponent.

Things were worse still at Auburn, where Cal backs rushed 26 times for 75 yards, an average of 2.9 per try. But Cal won the game, so it went largely unnoticed.

The Bears appeared to remedy the issue a week later in an easy win over San Diego State, even with Ott shelved by his ankle injury Thomas had a career-best 169 rushing yards and Cal’s backs carried the ball 29 times for 267 yards — a whopping 9.2 yards per attempt.

Then, in a 14-9 loss at Florida State, Ott returned and contributed to the Cal backs gaining 99 yards on 23 rushes, a suitable 4.3 yards per try.

It didn’t help Saturday that Cal again played without starting guard Sioape Vatikani, their most experienced O-lineman. He missed the first three games with a foot injury, then sat out the Miami game while recovering from  a neck or head injury at FSU. His status for Saturday’s game at No. 22 Pitt is unknown.

One thing that’s clear is that for the Bears to end their two-game losing skid and regain their early-season momentum, they’re going to have to find a running game.