Financial considerations at the team meant it risked money problems if it continued to keep on the paid Glock, rather than boost its coffers with the arrival of a pay-driver.
For a full analysis of the reasons behind the Glock decision, see this week's AUTOSPORT
And although that decision was a tough one to take - with Glock switching to the DTM with BMW - Lowdon believes it was the right thing to do because it has guaranteed the team's future for now.
"It is difficult decisions like this that secure the future of the team," he told AUTOSPORT.
"Everyone at Banbury has worked really hard for quite some time now on the 2013 car, and we think it is going to be a big step forward.
"Everyone is still pretty excited about the coming season. The key thing is that we cannot wait to get testing and see how the car performs – and I think everyone is keen to see how we are going to do this season because we have worked really hard.
"It is a team game, everyone has put a lot of effort in, and we are quite hopeful about it."
Although Marussia has not announced the launch date of its new car, the team is still on course to run at the first test that takes place in Jerez from February 5.