Ballack has been under fire recently from Leverkusen chairman Wolfgang Holzhauser for being the reason for the club's poor performance, but Leno does not share similiar sentiments.
The 19-year-old goalkeeper hailed the former Germany captain's experience, and said that it will be crucial for the club to learn from him.
He told Bild: "Ballack has tremendous experience. Especially in games like against Barcelona, he is important. Of all of us, he has played the most games in the Champions League. He can bring us pure experience,"
"[Ballack is] a really good guy [and] an absolute team player. Now we must help Michael."
Ballack is expected to leave the club at the end of the season after his contract expires and is reportedly considering a stint in the MLS.
Leverkusen meet Barcelona for the first leg of their Champions round of 16 tie on February 14 at the BayArena.