The Scotland international midfielder, whose early season form was hailed as “stunning” by Rangers manager Steven Gerrard, has been sidelined since sustaining a heavy blow to his head against his former club, Aberdeen, at Pittodrie on 5 August.
Jack missed the first leg of Rangers’ Europa League third qualifying round tie against Maribor at Ibrox last Thursday night and also sat out their Premiership victory at home to St Mirren on Sunday.
But the 26-year-old was given the all-clear by medical staff to rejoin training with the rest of the first-team squad yesterday. Gerrard is now optimistic Jack will be able to play a key role as Rangers take a 3-1 lead into the second leg against Maribor tomorrow evening.
“Ryan was back in full training yesterday, so, assuming he gets through today and tomorrow, he will be available for selection,” said Gerrard.
“It could be a huge boost because I think he is in great form and I think he has played a very important role for us so far.
“I think when you are going away from home and you have a slight advantage, you want to put people in your team that are going to help you get a positive result and Ryan comes into that bracket.”
Gerrard also had positive updates to deliver on the condition of another two of his midfield players, summer recruits Lassana Coulibaly and Scott Arfield.
Mali international Coulibaly delivered a man-of-the-match display in the first leg against Maribor but limped out of Sunday’s 2-0 defeat of St Mirren in stoppage time.
Arfield, who was troubled by a knee injury last month, was not even named among the substitutes at the weekend but Gerrard is hopeful both he and Coulibaly will be ready for Maribor.
“Lassana has recovered quite well and we don’t think it is a big issue. We think it is more down to maybe fatigue,” Gerrard told Rangers TV.
“He has posted some very big numbers in the last couple of games, in terms of distances and high speed, so I think it is just his body letting him know that he might need a little bit of a break at some point.
“It is a big game Thursday and we will have to wait and see what he is like in the next 48 hours before we make a decision on him.
“Scott was just rested at the weekend. He had two or three weeks out with his knee and then he came back and played two full games, one of them was with ten men against Aberdeen.
“We had to protect him at the weekend, so the idea was just to rest him. He had a little bit of a small issue but nothing major. Thankfully we got a win and actually rested him which is good.”
Rangers are looking to win three consecutive European two-legged ties in the same season for the first time since their run to the Uefa Cup final back in 2007-08.
The reward for completing the job against Maribor will be a play-off round tie against either Russian Premier League side Ufa or Luxembourg minnows Progres Niederkorn, the side who knocked Rangers out of the Europa League at the first hurdle last season. Ufa take a narrow 2-1 lead into the second leg of that tie in Luxembourg.
Rangers’ sole focus, however, is on overcoming a Maribor outfit who remain bullish about their prospects of overturning their first leg deficit. Coach Darko Milanic has been buoyed by his team’s 5-0 league win away to Gorica on Sunday.
“We expect to be able to create more opportunities against Rangers as well,” said Milanic. “We need to be aggressive, attack them in one-on-ones and also look to attempt shots from distance.
“We are optimistic. We know we have the quality we need in our team for this match and we know how to beat Rangers.”