Sir Alastair Cook believes England are right to back Jos Buttler to come good in Test cricket despite a disappointing winter with the bat.
Buttler averaged just 17.55, with a top score of 43, across five matches in New Zealand and South Africa and, coupled with a disappointing Ashes summer, has seen his spot in the side come under scrutiny.
Ben Foakes comes into the squad to provide competition for the gloves during the two-Test tour of Sri Lanka in March, but Cook cites leadership, continuity and Buttler's world-class talent as reasons to stick with him.
"Mike Atherton summed it up best when he said 'there is always going to be someone out of form'. That's just the nature of the beast, you won't have 11 players in the best form of their lives." Cook told Sky Sports News at the launch of cricket equipment manufacturer Gray-Nicolls' Tree Legacy Programme.
As part of that programme, Cook has planted 33 willow trees - one for each of the Test centuries he hit during his career, the initiative will see Gray-Nicolls plant a tree every time a player they sponsor scores an international ton.
Cook said: "Jos did struggle, by his own admission, with the bat in that South Africa series. He's going to a place now where he has scored runs before and, again, sometimes you do have to look at the long-term.
"Jos plays such a big part in the leadership of English cricket, as part of the Test team leadership group as well as in the one-dayers.
"You need that continuity with the players and I would rather back someone like him for a couple more games to find his form. He is a genuinely world-class player.
"Runs are his currency as a keeper-batter and he knows that. People like Jonny Bairstow - a world-class player - not going on the tour. He wants to come back. Ben Foakes as well - there is good competition.
"What encourages me is that they are starting to pick players in their rightful positions, where they have grown up playing for their counties, not putting round pegs in square holes."
Jennings last played a Test match in February 2019 in the West Indies, but Cook feels there was no other player he could have seen going to Sri Lanka ahead of him given his record in such conditions, and with lessons learned of not having the right cover in place during the New Zealand trip when Ollie Pope had to keep wicket after Buttler was injured.
"I think it's a fairly obvious decision to make," Cook added. "Rory Burns isn't there, so you need cover at the top of the order. In that New Zealand series they got burned a little bit because they only took one wicket-keeper. I know it was only a two-match tour, and there is a likelihood the keeper wouldn't get injured, but Jos did get injured.
"Suddenly you were in a Test match playing for England with a guy who has only kept six games and I think England have now learned who is the best top order cover to go to those conditions, and that is Keaton Jennings.
"If there is an injury you then have your best players available so I think it is a no-brainer.
"Whether what he does in Sri Lanka means he becomes first choice in June is not relevant. If he helps England win a series in Sri Lanka, with points for the World Championship, and to win back-to-back series away would be a great boost for English cricket and Joe Root.
"He's the solution at the moment, a good player of spin in the sub continent and that's where they are going. His two Test hundreds have come there. We don't know what is going to happen in June or July but I think England will pick the best four batters for the top three places available to them at the moment."
Sir Alastair Cook was speaking at the launch of Gray-Nicolls' new initiative, the Tree Legacy Programme, where he planted 33 willow trees - one for each of his Test centuries.