Statistically Speaking- Injuries in 2015 for Utah Football hurt

The Utes had to make do at one time or another without running backs, tight ends, quarterbacks, and wide receivers. While there’s no excuse for not being prepared for inevitable injuries, it’s fascinating to look at which players were critical to the Utes’ offensive success.

To analyze the Utes’ offensive production, I turned to comparative yard per play averages. This compares the Utes’ performance in the game in question against the average performance of the team’s defense and creates a score where 1 is average. I call it YDS+, after the similar OPS+ statistic used in baseball.

For example: over the 2015 season, Michigan allowed 3.6 yards per carry against all of their opponents. The Utes put up 3.5 yards per carry for a score of .97- not quite an average rushing performance but very, very close. Against Colorado, the Utes put up 4.15 yards per pass attempt. Since the Buffs gave up an average of 6.51 yards per attempt, this gave the Utes a score of .64 for that game- pretty bad. Against Oregon, Utah tore through the Ducks’ rush defense to the tune of 6.5 yards per carry, good for a score of 1.38 since the Ducks usually allowed 4.7.

You can track these scores over the course of the season to get a sense of the Utes trajectory as compared to their opponents. I’ve done so below, and included markers for when the Utes suffered injuries. The general slight downward trend is clearly punctuated in a few spots by injuries to critical players.

These graphs shows three critical injuries. There’s a clear drop when Travis Wilson isn’t playing (that’s not surprising to me, given my preseason analysis). Booker’s absence, tacked onto the end of the season, certainly doesn’t help matters. However, the clear and precipitous drop happens the moment Fakailoatonga goes down. These aren’t the only metrics that show what a critical piece Siale was.

I’ve used average YDS+ scores to quantify the drop in performance with the loss of certain players. I’ve included every player in this analysis, but take them with a grain of salt. A lot of these guys only missed a game or two, which creates a large margin of error.

The statistically significant drops come from Fakailoatonga and Booker in this analysis as well. Everyone knows how critical Booker was to the offense, but the collapse after the loss of a tight end is surprising. Fakailoatonga never picked up more than 45 yards in a game, but he was clearly instrumental to the smooth running of the offense. The loss in yards per pass attempt weren’t the only sign of Fakailoatonga’s importance; life got much more difficult for Travis Wilson after Siale went down.

From the first snap to when Fakailoatonga was injured, Utah gave up two sacks. Total. It was a major storyline in the early going as the Utes pass protection was near the best in the nation. Afterwards, they gave up 2.6 a game. This is despite the fact that the first five opponents had better sack numbers overall: an average national ranking a full 19 spots higher in the critical adjusted sack rate metric (31^st vs. 50^th).

Sacks aren’t the only area Travis Wilson felt the loss of this critical pass blocker. He threw an interception on 2.1% of his passes before Fakailoatonga’s injury; that number nearly doubled to 3.95% without the pass protection offered by the talented senior tight end. It’s hard to say whether this change came from having a cleaner pocket or someone to throw to on broken plays, but the gap is undeniable.

You can’t overstate the importance of Devontae Booker to the Utes in 2015. There’s no doubt that Utah’s offensive performance cratered after he was injured. The numbers tell a subtler story, though- that it was the loss of the tight end that precipitated the demise of the offense, and that Booker going down just made it official. If I had to pick one injury to take back, and one player to have healthy through the entire season, it wouldn’t be Devontae Booker. It would be Siale Fakailoatonga.

Need another stat to be convinced? Utah’s record when Siale was healthy: 5-0. Their record when he was out: 5-3. I’m comfortable putting the burden for at least two of those losses on this one injury. With Siale healthy, the Utes would have been the team to win the PAC 12 South and get a crack at Stanford and a shot at the Rose Bowl.