Januzaj has barely been it this season, he hasn't the work rate to start at wing back, something Lingard was selected to do on his debut this season but sadly a huge injury robbed him. Januzaj has also played upfront this season, he has not impressed as he doesn't get in behind the defenders nor does he offer pace. Januzaj had Raheem Sterling-ish season last season under Moyesy,Rodgers 8th place side, now that the side is thriving Januzaj is not up to standard.
Why will Lingard contribute more? He can play wing back, winger, No.10 and be a natural forward player, reserve form and loan spell form as evidence. Also Lingard may not be a great dribbler like Adnan, but he possesses the natural blistering acceleration and pace to get in behind defences, something Adnan cannot do off the ball.
I've always thought Lingard has more promise than Januzaj in the youth set up, then again it could be a case of Rooney VS Ronaldo again.
A link? Quotes from ManUtd.com By LVG, Physioroom, training updates etc, however now my info is outdated as its been 3 days since my last post.