During that period, Cleveland lost seven of eight games to fall to 19-19.
Since James returned for a Jan. 13 game against the Phoenix, the Cavaliers have won 12 of 13 games.
The four-time MVP has averaged 28.3 points, 6.9 assists and 5.7 rebounds over that span.
"I was able to just refocus my mind and reboot my system and it's definitely helped out a lot," James said, according to The Plain-Dealer in Cleveland.
Cleveland (31-20) plays at the Indiana Pacers on Friday.