But Barry is determined to fill the void.
The 2005 premiership star from Ireland is out of action for a month, leaving fullback Barry and dashing half-back Nick Malceski to pick up the slack for Saturday night's clash with Collingwood at Telstra Stadium.
While Barry's zig-zagging runs caused fans some anxious moments late in the match in their nine-point win over Hawthorn at the MCG two weeks ago, the left-footer says it's vital to keep taking risks in the last line of defence.
Sydney (6-5 win-loss record) can leap from 10th to fourth on the AFL ladder with a win over the fifth-placed Magpies, in a perfect build-up for an encounter with competition pacesetters the Cats in Geelong on June 30.
"It's going to a really big month for us," Barry said at a promotion for the Oncology Children's Foundation at Westmead hospital.
"It's an important month leading into the second half of the year," he added, pointing to upcoming clashes with Geelong, Fremantle (SCG) and Carlton (SCG).
"The top couple of teams over the past few years have had really good back ends of the season so we're hoping that's going to be the case.
"Nick Malceski is playing really well with his running game and Craig Bolton is running and carrying the ball."
Barry said he didn't see Kennelly come off the ground against the Hawks, but that he made a conscious effort to create some run.
"It is difficult to score heavily if you are continually kicking around the boundary line and being very predictable," he said.
"You have to bring the ball back into the corridor and try to create a few one-on-ones.
"It was definitely a bit of a feature last week and hopefully we can continue that on Saturday night."
Barry said the Swans had "really struggled" early against the Hawks, before a stinging address from coach Paul Roos at quarter-time.
"It was almost our season on the line," Barry said.
"The way we played in the last three quarters is like the way we know that we can play and (we did it) against Hawthorn who are one of the better teams going around at the moment.
"We have been struggling like a lot of teams but if we do have a win we could possibly get into the top four and really (kick-)start our second half of the season."
Barry is likely to match up on Collingwood key forward Anthony Rocca.
"They've got a formidable forward-line with Rocca and Alan Didak so it is going to be a pretty difficult task," Barry said.
Swans midfielder Jude Bolton described the Collingwood game as "crucial" to the side's finals hopes.
"It's massive. We understand the enormity of the game," Bolton said.
"If we can start building on some good form and putting some good games together and hopefully we can gain some consistency and confidence from that."
