For the second time this campaign, Gary will step up from reserve team manager to head up first team affairs, where he will again be assisted by Terry McPhillips and Tony Grant.
The announcement follows discussions with the club's owners, officials and the League Managers Association.
"We will approach the situation exactly as we did previously," said Gary, who enjoyed three wins and a draw during his previous spell earlier in the season following Henning Berg's departure.
"There is plenty of work to be done and we will treat the challenge very much on a game-to-game basis starting with Blackpool here on Friday. We will work hard and give it our best shot and all we ask is that the playing staff and the supporters get right behind the club."
Tickets for Friday's 3.00pm match against Blackpool are on open sale for this match and are priced at £19 Adults, £12 Seniors and £7 Juniors.