LONG READ The Johnny Sexton succession plan

We are approaching the final act of Johnny Sexton’s career. The man with Heineken Cups, Lions Series wins, Six Nations trophies and Grand Slams has one prized asset to add to his glittering CV, but like any thriller, no one knows quite how the denouement will play out. Sexton hasn’t played a minute of rugby since the 2023 Six Nations, through injury and a ban for insulting the referee during the Heineken Cup final in May and there is no guarantee he will go the distance for the entirety of the World Cup. So who are his deputies, and how ready are they to assume the role of playmaker, marshalling a gifted backline through the minefield of a World Cup campaign? Jack Crowley and Ross Byrne are multi-talented pivots, ready to step up, when called upon as the data below shows us…

1. Jack Crowley’s emergence at Munster

Crowley made his Munster debut against Ulster in January 2021, this first graphic shows his gametime (10-game rolling average) over the following two seasons, compared to the two main Munster players competing for the 10 jersey at that time; Ben Healy and Joey Carbery. In the 2021/22 season, Munster relied heavily on either Healy or Carbery as their fly-half option, with Crowley never averaging more minutes than both of them that season. Although he did amass 455 minutes in 2021/22, this was mainly due to injury cover for Carbery, who was kept out of action for four months with a fractured elbow picked up in December 2021. Crowley ended 2021/22 without featuring in Munster’s last nine games, resulting in his 10-game average sitting at just 7 minutes.

Crowley’s increase in game time in 2022/23 mainly came at the expense of the Edinburgh-bound Ben Healy, with Crowley overtaking Healy for 10-game average minutes in December 2022 and going on to play a further 936 minutes that season, with Healy only playing an additional 332. Crowley’s 80 minutes vs Northampton in the Champions Cup on January 14^th 2023, marked the first time that his 10-game average minutes exceed both Carbery and Healy’s. Crowley further established himself from that point, going on to average 53.3 minutes over the last 10 games of the season, with Carbery (28.8) and Healy (20.6) well behind.

2. URC performances of Jack Crowley and Ross Byrne over the last two seasons

The next part of this article will look at the performances of Jack Crowley in the URC over the last two seasons, compared to his main rival for the Ireland No 10 position, Ross Byrne. The above graphic displays their per 80-minute performances over six different areas of the game, compared to all other URC fly-halves to have played at least 800 minutes across the last two seasons. The top three graphs look at the players’ effectiveness with the ball-in-hand, showing how Crowley opts to carry more than Byrne, leading to him making more dominant carries and metres gained. Looking at passes made per 80, Byrne averaged over nine more passes per 80 in 2021/22, but both players averaged 22 passes per 80 in 2022/23, yet Byrne averaged more try assists per 80 than Crowley, across both seasons.

The bottom section of the graphic visualises the players’ defensive and kicking game, with both individuals making fewer dominant tackles in the 2022/23 season, however Crowley’s tackle completion was over 10% higher than Byrne’s. Byrne has averaged more kick metres across both seasons, whilst a higher percentage of Jack Crowley’s kicks were retained in 2022/23, although it should be considered that a player’s kicking game is somewhat reflected by their teams game plan, as well as Crowley playing six games in 2022/23 at 12. The final plot of the graphic shows each player’s goal kicking efficiency over the last two seasons, with Byrne outperforming Crowley from the tee in both seasons.

3. Jack Crowley’s goal kicking

This next section picks up where the last one left off; goal kicking. This may turn out to be the deciding factor when it comes to choosing between Crowley and Byrne to back up Sexton. For the past two URC seasons Crowley has kicked at under 70%, whilst Byrne is kicking at 85% or over. The graphic above maps out all of Crowley’s goal kicks in that time and incorporates Opta’s expected kick success metric, giving an expected points value. In the 2021/22 season, Crowley kicked 30 points, however that was 4.9 fewer than Opta expected from the difficulty of his kicks, whilst in 2022/23 he kicked 30 points from an expected 33.3. On the kicking map itself, the size of the plots represents Opta’s kick prediction %, with larger plots representing kicks with a higher likelihood of success.

4. Performance of Ireland’s fly-halves since 2022

This section will now turn its attention to the performances of Ireland’s three fly-half options, Johnny Sexton, Jack Crowley and Ross Byrne, when playing for Ireland since the start of 2022 (not including Saturday’s win over England). The accompanying graphic illustrates the players per 80-minute performance as the difference from the mean, for a range of metrics. Firstly, the graphic shows the disparity of minutes between the three players, with Sexton playing 765 minutes whilst Crowley and Byrne are under 200. In general, Sexton is leading the three on the majority of metrics, topping try and break assists, metres gained, percentage kicks retained, tackle completion percentage and tackle dominance. Ross Byrne appears to offer a more conservative option, with the lowest metres gained with ball in hand but highest metres kicked, as well as conceding the fewest turnovers but completing the lowest percentage of his tackles. Crowley’s performance is similar to Sexton’s across a few metrics, almost matching him on metres gained, kick metres and tackle completion.

5. Goal kicking for Ireland

This final section continues the theme of looking at the performances of Johnny Sexton, Jack Crowley, and Ross Byrne in an Ireland shirt, by assessing their goal kicking efficiency, again incorporating Opta’s kick predictor. Unsurprisingly, given the minutes he’s played, Sexton has far more goal kicks (56) than both Crowley (8) and Byrne (11) and is sitting at 79% accuracy, but only 0.4 points below Opta’s 104.4 expected. Although Crowley has only had 8 kicks at goal, he’s nailed 7 of them, putting him 2.6 points ahead of Opta’s expected points, whilst Ross Byrne, who has kicked at goal 11 times for Ireland, has missed three, giving him the lowest success percentage of the three.