Staying fit is Luke Marshall's main priority as Ulster try to juggle their resources in an injury-hit backline.
He has played alongside James Hume and Stuart McCloskey this season and moves to inside centre to partner Matt Faddes in Friday's Pro14 home game with Zebre.
"James was very unlucky pulling his hamstring last week just after making a line-break," Marshall said.
"We haven't been too lucky with the fitness of the centres so I'm just trying to keep fit at the minute."
Ulster's options have been stretched further with wings Rob Balacoune (knee) and Michael Lowry (ankle) unavailable, while Rob Lyttle has recovered from a back injury to start against the Italians.
Promising inside centre Hume lasted just 40 seconds of last week's home win over Cardiff Blues before being carted off with injury.
New Zealander Matt Faddes replaced him, with fit-again Will Addison at full-back, but Marshall is relaxed about the revolving door beside him at inside centre.
"They are all good players, they make it pretty easy.
"Matt came off the bench on Friday and it was easy to fit in with him, he's a smart rugby player and he makes my job easy as well.
"James got another nasty one on Friday, which is really unlucky given the way he's been playing, but he'll get himself back fit and into the frame. He'll play a lot of games this season."
More in the tank
Ulster have won three of their opening four games in the Pro14 but performances have been mixed.
After a very bright start, they were unconvincing winners against Cardiff Blues last week but Marshall has insisted the squad has 'more in the tank'.
"It's a positive we're still winning, we have two bonus point wins.
"It was frustrating [against Cardiff] that we didn't kick on, and we probably could have gotten a bonus point if we'd played to our full potential, but we're still winning, and to know we've still got more in the tank is a positive.
"It's just how we bring that out in ourselves."