Adrian was banned for three games and has sat out the last two after being sent off in the closing stages of West Ham United's 2-1 defeat to Leicester City in the first home game of the season.
An appeal against the severity of the ban – West Ham wanted it reduced to one game – was dismissed.
The club's desperation to appeal gave rise to suggestions that Bilic, like many West Ham fans, was worried about understudy Randolph's ability to perform on the Premier League stage in the Spaniard's absence.
But while Randolph conceded four in a 4-3 defeat to Bournemouth in the very next game, he was not to blame for any of the goals and Hammers fans actually praised him for keeping them in the game at 2-0 down with a string of fine saves.
In his next game up at Anfield, Randolph was part of a side that rewrote the history books.
In securing West Ham's first win at Liverpool's home ground in 52 years, the former Birmingham City 'keeper kept a clean sheet as Bilic's men ran out 3-0 victors.
And while West Ham's excellent defensive display meant he only had one shot to save in the 90 minutes, Randolph's organisation of the defence in front of him and his distribution were first class.
Adrian completes his three-match ban when West Ham host Newcastle United on Monday night and is expected to take his place back in the starting XI.
'He works hard and gets his rewards'
But talking to West Ham's official website, Bilic's 'keeper coach Woods – a former England international and coach – has backed Randolph to keep surprising people by making it hard for the manager to drop him.
"What you do as a goalkeeper you've got to go out there and your aim is to obviously play well and keep a clean sheet, he's (Randolph) done that," Woods told whufc.com.
"It's not like you can affect scoring a goal. Yes you can punt one down the field and get one like that but you just have to keep everything right at the back and hopefully the players in front of you do their jobs as well.
“He didn't have a lot to do but when he was called upon (at Anfield) he did very well and coming out of the game his confidence will be even better. He works hard at his game and he got his just rewards."
Role reversal for Adrian... for now?
Bilic's dilemma will be intensified should former Birmingham City 'keeper Randolph help the east Londoners end their home hoodoo against the Magpies – they have only won three times at Upton Park all year.
While he will have been kept on his toes by Woods in training, Adrian may be somewhat rusty after his enforced five-week break and if he is thrown straight back in and makes a mistake, it could leave Bilic red-faced.
Some fans would argue that Randolph signed for the club in the summer fully aware of his place in the pecking order and may get another chance in cup matches.
But on the other hand, with a trip to Leicester in the League Cup looming after the Newcastle game, perhaps the roles will be reversed and Randolph will keep his place for Premier League games while Adrian will be eased back in against the Foxes on a potential revenge mission?