A worker prepares 196 Elm St., in Davis Square, to become the bricks-and-mortar location of Knucklebones, a provider and seller of athletic services and goods. The grand opening is Monday.

Knucklebones, a provider and seller of athletic services and goods, has its “epicenter” grand opening Monday in Davis Square (at 196 Elm St. North, the very edge of Cambridge’s border with Somerville), taking over half the space emptied by the Caning Shoppe when it moved to Somerville’s Wilson Square over the summer.

To celebrate, the site is open for free play from 9 a.m. to 6 p.m. for children age six month to 6 years, according to an announcement from Mitch Zeisler, who founded Knucklebones in 2004, and the rest of the 11-person team.

“Come by and meet the KB team, register for upcoming classes, find out more about our retail and, of course, play with the coolest and most unique athletically inclined products around,” the announcement says.

The team has mostly traveled to clients to host custom events such as birthdays, but its “Knucklebones Epicenter of Athletic Services” allows it to bring in — as part of what Zeisler describes as the site’s first stage — play groups, programs, private events and field trips, as well as roll out a retail catalog with athletic equipment and backyard games.

Stage 2, projected to come by Jan. 1, will be the filling of the Elm Street space with a full retail store, and the final stage is to bring in athletes, writers, chefs, educators and health professionals to talk about healthy living. (The grand opening was originally announced for October.)

Also coming to the area is Michaels, the Irving, Texas-based art supply chain with 1,054 sites throughout Northern America. Founded in 1984, the chain expanded quickly and went public but was taken private again in 2006 with a purchase by Bain Capital Partners LLC and The Blackstone Group. Michaels also owns the Aaron Brothers and Artistree chains.

It fills the massive underground space left empty when Burlington Coat Factory left the Gravestar Inc.-owned Porter Square Shopping Center in June 2008 and could steal some of the lower-end shoppers from the Paper Source at 1810 Massachusetts Ave., only 0.2 miles and some five minutes’ walk away.

So far there is only a temporary sign over the Michaels site indicating the store is on the way — but the sign also says the store is hiring and leads potential employees to the store website.

Thanks to Ron Newman for reminders on these developments.