Tredwell would probably have been playing drinks waiter had Moeen been fit to start the tour, but was instead handed a second cap five years after his first.
He responded admirably, taking four for 47 as the West Indies were bowled out for 295.
England recovered from a shaky start to end the day 220 ahead on 116 for three, with Tredwell’s case well made.
Asked about Moeen linking up with the side on Saturday, he said: “It’s probably at the back of my mind but you try not to think too deeply about that.
“I wanted to give them a bit of a headache, shall we say, and hopefully I’ve done that now.
“So it’s over to the people who matter to make that decision going forward in the series. There’s another important innings to come so hopefully we can knock them over and get the win.”
If passed fit and ready by England’s medical staff, Moeen seems a good bet to earn a recall next week but Tredwell is not the only vulnerable party.
Jonathan Trott’s return after 18 months out has been a trial, with scores of nought and four at the head of the innings.
With captain Alastair Cook also short of runs, a new face in Trott’s position might yet appeal.
Tredwell was the typical team man when pressed about the opening pair’s struggles thus far.
“I guess whenever you go through a challenge – for wickets or runs – it can get on your mind at times, but they’re both strong characters so I’m sure there’ll be scores around the corner,” he said.
“It’s their own issue but we’ll stick with them. They’re fine players.”
West Indies centurion Jermaine Blackwood was more forthcoming when discussing Cook’s search for form.
He did so from a position of strength, having chiselled 112 not out to record his maiden Test century.
The home attack have done a good job of keeping Cook down in two innings to date, having focused on testing him in the channel outside off stump.
“They were bowling full and the ball was swinging a bit. Alastair always drives so we were trying to drag his hands away from his body and Jerome Taylor did that very well,” said Blackwood.
“He was bowling to a plan. Taylor always sticks to a plan and when it works you celebrate.”
England had their own plans against Blackwood, mostly involving short pitched bowling at his body.
He came through unbeaten but not entirely unscathed.
“I’m from Jamaica. We have a lot of fast bowlers,” he said.
“I’m not afraid of any short balls. The bowlers will get tired and that is when I will damage them.”