Should We Worry About Alfredo Morelos?

Written by: Matt Rhein @TheBackPassRule

At first, this was going to be a complementary piece to this article, discussing the five shots in the SPFL that had the highest xG value and were missed. However, something was very apparent looking at that list. Rather, someone was very apparent. Rangers striker Alfredo Morelos appeared on that list 3 times, more than any other player in the league.

The beginning of the 2017/18 SPFL Premiership season seems ages ago, though Alfredo Morelos might wish we still were in that time. The Colombian striker got off to a fast start in his Rangers career, scoring 6 goals before his first match-up with rivals Celtic in September. I wrote about how impressive the striker had been up to that point on The Backpass Rule. Of course, that game saw the beginning of an alarming trend for Morelos of missing high probability scoring chances in big games.

While Morelos' season with Rangers had a few more moments like the above in September, he actually had some promising statistics. He finished second in the league in goals with 14. He led the league nearly the entire season in xG total at 20.84 (Expected Goals, or a measurement that assesses the probability of a chance being scored) and had the highest xG per 90 of any player with at least 1,200 minutes played at 0.72.

Courtesy of Ian MacNicol/Getty Images

Courtesy of Ian MacNicol/Getty Images

In addition, Morelos had also had metrics suggesting he can help facilitate on attack, in addition to taking matters into his own hands. He had an xA (Expected Assist, or measuring the quality of the pass leading to a shot) of 5.64 and 0.20 per 90, which was 23rd in the league. He also had an xSA (Expected Secondary Assists, or measuring the quality of the pass before the pass leading to a shot) total of 3.65 and 0.17 per 90, good for 13th in the league. 

Now, there is no point in re-litigating whether or not there was a bid from China for £8,000,000 for Morelos in January. Whatever you believe about that story is unlikely to be changed at this point. However, with stats like the above, it is certainly plausible that some team somewhere would be interested in his services at that time.

Yet after that whole saga, something seemed to change for the striker. With the big money linked to his name, there seemed to be more pressure on him and it appears that it at least had some effect on him. He seemed to miss more high profile good chances and started to develop the reputation from some that he was a poor finisher. Rangers supporters demanded on-loan striker Jason Cummings start ahead of Morelos and Graeme Murty made that change in the lineup. So did the pressure get to Morelos during this time? Perhaps, but there could be another explanation as well.

Morelos G & xG per 90.png

Looking at his xG numbers over the course of the season in the graph above, we see Morelos hovered around the 0.70 xG per 90 mark. These numbers mean he was able to consistently get good scoring opportunities throughout the season. This is an important trait for a striker, as if you are able to consistently create high probability scoring chances, you will likely score goals.

Of course, creating good chances is not the whole story for a striker though, you need to finish them. Comparing Morelos' goal scoring per 90 to his xG per 90 in the graph above, we see he overachieved his xG for the first portion of the season but then underachieved for most of the rest of the season. To put it plainly, he at first scored more than we would expect and then scored less than we would expect. This is a pretty wide swinging variance for a player over the course of a season. So perhaps Alfredo Morelos was not feeling any pressure but simply was the victim of regression to the mean.

Morelos Conversion and Accuracy.png

If we look at Alfredo Morelos Conversion Rate (Goals Scored divided by Shots Taken) and Shot Accuracy Rate (Shots on Target Taken divided by Shots Taken), we see a similar story. Keeping in mind that an average conversion rate is around 11%, we see that Morelos was overachieving greatly in the first ten matches of the season, with a conversion rate between 20-40%, before regressing over the season to a slightly higher than average conversion rate at 15%. Simply put, it was highly unlikely Morelos was going to be able to continue to score at the rate he was at the infancy of his first SPFL Premiership Season.

Modern Fitba colleague Seth Dobson has previously written about the stabilization of conversion rates. Seth shows that it takes about 1,200 shots for conversion rate to stabilize. With both Seth's work and Alfredo Morelos' conversion rate numbers in mind, one could rubbish the "poor finisher" tag Morelos has received. Yet, there is another stat we want to look at before we throw that unwanted distinction away.

While the Colombian striker's conversion rate numbers should not sound the alarm, perhaps his Shot Accuracy Rate numbers should. Like all of his other statistics, the rate at which he got shots on target was higher at the beginning of the season than the 40% typical average for Shot Accuracy Rate before regressing around the same time all of his other metrics regressed. What may sound the alarm here is this number fell below the average rate of 40% and stay below that thresh-hold for the rest of the season, finishing at 31.52. This means less than a third of Alfredo Morelos' shots ended up on target in SPFL Premiership Play. While Accuracy Rate is similar to conversion rate in that it takes a long time to stabilize, it certainly is a reason to pause when thinking about Morelos.

Courtesy of Russell Cheyene/Reuters

Courtesy of Russell Cheyene/Reuters

So with all that data, we come back to the initial question that is the title of this article. Should we worry about Alfredo Morelos? The perhaps unsatisfying answer is maybe. There certainly seems to be an element of Selective Perception, or the tendency to notice evidence that supports our beliefs and ignores evidence that contradicts it, when it comes to the Colombian striker's play. Many think "Alfredo Morelos didn't score against Celtic, so he must be pish", probably ignoring his good metrics such as his Goal total, xG, xA, and xSA assist numbers. They are not interested in his still higher than average goal conversion rate at season's end.

Yet there are still some warning signs, such as regression in Morelos' goal scoring and shot accuracy last season. Could Morelos have another swing in variance and see these numbers positively regress to the mean again? Certainly, especially considering he was half-way through the Finnish season when he arrived at Rangers. He could have just run out of gas. Seeing these numbers raised next year will certainly help us indicate if a rested Alfredo Morelos can bounce back.

Personally, I have been bullish on Morelos since his arrival and suspect we will see him in better form if he is back at Rangers next season, albeit probably not at the red-hot form he had when first arriving. This season likely showed us he could not continue the overachieving we saw from him during that time. If we do not see improved shot accuracy numbers from "El Bufalo", he will not shake off the poor finishing reputation he has developed.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.