"Not just this season, but there was a long period in the middle of last season where I think he has been the best defender," Southgate told Sky Sports.
"He's got very good composure on the ball. He's got the reading of the game, he's aggressive in his defending - which I like - and I think he has got fantastic experience, although he is still only relatively young."
Jones has struggled with injuries in recent years and the game against Slovakia will mark only his eighth competitive appearance for England but Southgate believes the centre back, who made his national debut in 2011, can boost his team.
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"Obviously he has missed a lot of football. I remember watching him against Spain under Fabio (Capello) so we are going back quite a long way since he made his debut," Southgate said referring to former England manager Fabio Capello.
"He's had great experiences with club and country. He organises well, he competes well so I'm delighted we've been able to involve him this time and it was clear the other night what he brings to the team."
England lead Group F with 17 points after seven games and Slovakia sit two points behind in second position. With three games remaining, a win at Wembley Stadium would all but secure England's World Cup qualification.
(Reporting by Aditi Prakash in Bengaluru; editing by Alexander Smith)
