"He will give the other players confidence," said the Glasgow backs coach.
"Daniel only arrived just over two weeks ago and it was always our intention to have a look at him, which is why he's come on as a sub in our last two games.
"He's a goalkicker, a very confident player and also a good organiser. Calvin is a quality player, no doubt about that, but he has to be more consistent. Missing the kicks affected his confidence, but then the whole team failed to perform against Connacht.
"This is a great opportunity for Dan and the others who have come in to test themselves against Munster, the Celtic League champions.
"When he came on last week he got things moving. We need him to lead the back line and his kicking will be very important."
David Millard was on the bench last week, but Sean believes he's ready to make the step up. "His attitude has really come on and he has plenty of pace, which is invaluable," Sean said.
"The guys have got to get back in the saddle after last week. Everybody is putting the effort in, so it will be important for us to show what we are capable of.
"This is a big game for us for a number of reasons, not least confidence. We are still building and for us to go through to the last four of this competition would be tremendous."