With 4 important (read: insane) catches in 2 games, Ravindra Jadeja has proved that you don't need to be a part of the playing XI to contribute towards the team's success.
Filling in for an injured KL Rahul, he took a beautiful catch during India's match against England, to dismiss Jason Roy. Jason had already been given a second life after India's decision to not opt for DRS and his wicket was very important to break his solid partnership with Jonny Bairstow.
Fielding at long on, he dived and took a brilliant catch to send Roy running back to the pavilion.
There’s a reason he’s called “Sir” Jadeja. Top top catch !! Game changer— Suresh Raina🇮🇳 (@ImRaina) June 30, 2019
He also helped with Ben Stokes dismissal and hence played a huge role in somewhat restricting the English side, which was on a run-spree.
That was a blinder from Jadeja. Purely his wicket. Time to tighten things. Come on India. #IndvEng— Mohammad Kaif (@MohammadKaif) June 30, 2019
Similarly, he walked in, in place of Shikhar Dhawan during India's match against Australia and took 2 great catches to dismiss Glenn Maxwell and Adam Zampa.
Jadeja makes presence felt with a stunning catch to remove Maxwell. The end is nigh for the Aussies. Didn't quite manage run momentum purposefully for more than 30 overs, leaving too much to do towards the end. Match not over yet, of course, but from here only a miracle...— Cricketwallah (@cricketwallah) June 9, 2019
All that to say that he realises the importance of good fielding and it doesn't matter to him if he is a main part of the side or a substitute.