It is a substitution Graham Potter has opted to make in each of Chelsea's previous three matches – and it is hardly a like-for-like change. The mercurial Joao Felix off; the indefatigable Conor Gallagher on. It hasn't exactly been difficult to deduce Potter's thought process.
Against Leeds United, Gallagher was introduced in the 68th minute. Chelsea held a one-goal lead and that needed desperate protection given previous results. The academy graduate provided that as he shut down space, closed down opponents, and chased down lost causes.
It was a repeat scenario three days later when Borussia Dortmund visited Stamford Bridge in the Champions League. Potter's side had overturned a first-leg deficit to lead the tie 2-1. It was a slender advantage that needed defending. So the Chelsea head coach once again turned to Gallagher.
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He replaced Felix in the 67th minute and was handed the duty of guard dog by Potter; it's why the England international attempted the second-most tackles (three) and challenges on dribblers (five) of any Chelsea player, per FBRef. Just as tellingly, Gallagher completed just two passes. His task was to impact the game without the ball.
Such a role may feel somewhat reductive, but it does amplify Gallagher's biggest strengths. Few in the European game can match the 23-year-old for energy and is unrelenting in his desire to hunt down possession. And it's these traits that resulted in Thomas Tuchel believing Gallagher was a successor to N'Golo Kante in midfield.
Not that Gallagher was hugely keen on the comparison. ‘It’s obviously a massive compliment even if I’m half the player Kante is," he said in November. "I feel like NG is the best midfielder in the world, he probably still is now when he’s fit."
It shouldn't be overlooked that this campaign is Gallagher's first in the senior Chelsea side – and that has come with an emotional load given the midfielder and the majority of his family are long-time supporters of the club.
Perhaps that emotion has got the better of Gallagher on occasion this season; there have been games in which his tackling has been impetuous and his passing forced. He appeared – at least to many in the stands – too eager to haul the Blues out of their slump in January and February.
In the previous three matches, though, Potter has harnassed Gallagher's dynamism. That was evident once more against Leicester City on Saturday. Gallagher was introduced at the interval, again for Felix, with Chelsea ahead. But the Foxes had consistently outnumbered the Blues in midfield.
“I felt we needed someone who could win the ball," explained Potter after the game at the King Power had been won. "We needed a different profile and I thought Conor was fantastic.”
Gallagher brought balance to the Chelsea midfield and helped restrict the threat of James Maddison – his four successful tackles and interceptions were only bettered by Marc Cucurella. There was also one crucial goal-line intervention made after Kepa Arrizabalaga had flapped at a cross and left Harry Souttar with what appeared a simple finish from close range.
It's likely another spot on the bench awaits Gallagher this weekend for the visit of Everton, who sounded out a move for the midfielder in the January transfer window. That may not be enough for the academy graduate long term but he does appear to have found his niche under Potter – and has played an important role in helping Chelsea turn their stuttering form around.
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