Recent injuries to Rory Best, Iain Henderson and Stuart Olding have not done Ulster any favours, but nevertheless there are make-or-break matches to be won in the PRO12 and Heineken Cup in the coming weeks if they are to compete on both fronts.
In addition, Trimble knows he must shine if he is to work his way into Ireland coach Joe Schmidt's plans for the Six Nations Championship which gets under way at the start of February.
His assessment of his own game right now is: "There's a few things to work on, so I'm working hard while at the same time not trying to force it. If I just try to go out and relax and play a bit, then hopefully what I do well naturally should come through.
"There's definitely a couple of things I'm a little bit frustrated about in my own game, so there's no point in me looking at anybody else; I've got to sort it out myself."
Invited to elaborate on the source of that frustration, Trimble's impressively honest self-analysis sees him reply: "I'm not concerned about making massive line-breaks or scoring tries from half-way. It's just small things – making my tackles, ball-presentation, decision-making, spacing in defence, reading the game.
"Dinger (Ulster defence coach, Jonny Bell) is putting a lot of pressure on us to get up in the line and that's something that will work well in my game. But you have to make a last-minute decision and it's high intensity. So these are all things that I just want to be accurate in my game."
At that the conversation evolves to his Irish aspirations. How deep is the hunger to add to his 50 international caps?
"Oh it's still there," is his very definite answer.
Asked what feedback, if any, he has had from Schmidt, he replies: "There's a few things I need to work on – those things I've already mentioned, really. Joe has highlighted them, but I was fully aware of them myself. I know what they are, I know what I need to work on.
"I think that if I can get those things right there's no reason why I can't get back in the mix. So I'm looking forward to doing that.
"It's up to me to make sure that I get my game right and not be concerned about a coach's selections or competition for places or any of those things.
"In my mind it's very simple; just get my game right and then see what happens. There is an opportunity."
Asked if he feels playing in an Ulster back three unit which includes fellow-Irish wing Tommy Bowe helps his own international prospects, Trimble replies: "I enjoy playing with Tommy, I like the way he plays and I think we complement each other a little bit. But I don't think it's any more of a benefit than if I was playing with anybody else."
Is he happy to see Craig Gilroy at full-back for Ulster?
"I think that's working very well. He's definitely got the running game – he showed that on Friday night against Edinburgh. He's got the kicking game, too, and positionally he's very good," he said.
"But Ricky (Andrew) came on against Edinburgh and produced a great display at full-back, too. He's young – maybe not as young as Gilly, I'm not sure – but he's very assured. He bosses it, he commands the back-field and as a winger it's very reassuring to know what's going on back there.
"They're both very good, so there's a lot of competition, but that's true everywhere in this team."
This afternoon in Parma it is vital that there is a positive result for Ulster and Trimble.
"It's going to be tough," he admitted. "Zebre aren't the side they were last season. They've come on. They got that win against Cardiff and their tails have been up a little since then. They play a decent brand of rugby, too, and they can threaten from anywhere, really.
"We done a good bit of homework on them this week and now it's important that we take that onto the pitch.
"They should have beaten us last year. I wasn't playing in that game so I don't know what the mindset was, but I know it's important we get our mindset right this time."
The availability of some of the Ulster players involved in the autumn internationals prompted Trimble to say: "We're in decent shape, though it's just a shame we've lost one or two as well – Rory (Best) picking up a knock and Hendy (Iain Henderson) – so the next few weeks will be a bit of test for us.
"But it'll be good trying to get straight back into the momentum and hopefully able to pick up where we left off last weekend.
"Winning against Zebre would set us up nicely for going back into Europe next weekend."