The scrum-half has enjoyed a long and successful run at nine but with Springbok Ruan Pienaar set for his comeback against the Scarlets next week, he hopes to impress against Glasgow this evening.
“Certainly Ruan is a great player, the most high-profile player we’ve ever had at Ulster,” said Marshall.
“I have had a good run and I suppose I was just keeping the jersey warm for Ruan. There were times last year when he got us out of jail. Tonight could be a big chance for me to put down a marker. I need to take every opportunity because I want to see myself playing for Ulster and I have ambitions beyond that as well.
“I want to play international rugby and that should be every player’s goal. If you look at the scrum-half position in Ireland now compared to three or four years ago, there’s a lot more competition.
“I started the season reasonably well, but nobody, including myself, was firing after that and we struggled with leadership issues when our World Cup players were away.
“If the team does well, individuals do well. I wasn’t happy with my form, but then a lot of players felt that way. Hopefully, the Heineken Cup performances can kick us on because we need to improve our league position.”
Stephen Ferris, Rory Best, Chris Henry and Craig Gilroy will be rested following the Leicester loss with Robbie Diack, Andi Kyriacou, Willie Faloon and Adam D’Arcy all being brought in.
GLASGOW: S Hogg; D Lemi, T Nathan, G Morrison, F Aramburu; D Weir, H Pyrgos; J Welsh, P MacArthur, M Cusack; T Ryder, A Kellock (capt); R Harley, J Barclay, R Wilson.
Replacements: F Gillies, R Grant, M Low, R Gray, C Fusaro, C Cusiter, A Dunbar, C Shaw ULSTER: A D’Arcy; A Trimble, D Cave, N Spence, S Danielli; I Humphreys, P Marshall; T Court, A Kyriacou, D Fitzpatrick, J Muller (capt), D Tuohy, R Diack, W Faloon, P Wannenburg.
Replacements: N Brady, P McAllister, A Macklin, T Barker, M McComish, I Porter, P Jackson, I Whitten.