The Tynecastle attacker rose from the bench to make his first appearance since the 2-2 draw with Ross County in September and score the only goal of the game in Saturday’s 1-0 win at Dundee.
Black, who is close friends with the Hearts No.7, believes Neilson should “get his bags” if he doesn’t give Walker more of a chance going forward.
He wrote on his Instagram page below a photo of Walker celebrating at Dens Park: “If this picture isn’t a wake up and ‘give me a chance’, then Robbie needs to get his bags and do one end of, kept him in the job with winners more than once this year. Time to start looking closer to home at your heart n soul of the club @jamiewalker7.”
Neilson has stated twice in the past week his admiration for Walker and his desire to keep hold of the player in the January window despite his lack of regular playing-time this season.
St Johnstone and Livingston are two clubs reportedly interested in acquiring the 28-year-old, who is out of contract at the end of the season.
Black earned man-of-the-match honours in the 2012 Scottish Cup final when Paulo Sergio’s side defeated Edinburgh rivals Hibs 5-1 at Hampden Park.
The midfielder spent three seasons with the club before moving on to Rangers. He arrived the summer of 2009 when Robbie Neilson departed the club for Leicester City.