St Kilda Coach Alan Richardson is thrilled emerging key forward Paddy McCartin has put pen to paper and recommitted to the club.

McCartin signed a two-year contract extension on Sunday night, tying him to St Kilda until at least the end of 2020.

The highly-rated 21-year-old returned to training on Monday after overcoming an ankle injury that sidelined him before Christmas.

“We’re rapt. Paddy is going to be a really exciting player for our footy club,” Richardson told saints.com.au at Geelong Grammar on Tuesday.

“He’s just joined back into training; he’s got himself in really good shape.

“I think the fans are going to enjoy Paddy for a really long time; he’s going to be here for a long time, so it’s really exciting news.”

With the inaugural AFLX competition less than a month away, Richardson said St Kilda will prepare specifically for the hybrid version of the game and use the competition as another tool to prepare for Round 1.

Second-year Assistant Coach Ben McGlynn will coach the Saints’ AFLX side, with fellow Assistant Coach Lindsay Gilbee and St Kilda's Performance Analysis Manager Robbie Chancellor also driving the program.

“The reality is most clubs do small-sided games as part of their prep; it’s quite taxing; it’s almost harder than the game itself,” Richardson said.

“So from a conditioning point of view, there are some real positives in training that way. There are certainly some real specifics to AFLX that we’ll train; we’ve already done a little bit.

“Benny McGlynn is in the chair, so both he, Lindsay Gilbee and Robbie Chancellor will drive that up.

“We’ll start to step that up a little bit up until the 16^th of February when we play.”