The encounter is one of three RBS Premiership matches taking place today with Gala welcoming Aberdeen Grammar to Netherdale and Boroughmuir taking on Dundee HSFP.
During the week the rumours that had been circling in the Borders for a while became reality when Chalmers announced he would be moving south to take on a coaching role with Chinnor, who play in English National League Two South. He is still with Melrose at the moment, though, and he would like nothing better than to help the club secure a British & Irish Cup spot for next season by finishing in the top four.
The hosts go in to the match with former skipper Jamie Murray at full-back with Fraser Thomson on Glasgow Warriors duty while Edinburgh hooker Alun Walker again slots into the back-row after benching for Scotland A last week.
Accies, who are in seventh place, travel with a young and settled squad and are keen to gain points to lift them even further away from the bottom two.
A few miles down the road should Gala defeat Aberdeen Grammar with a bonus point then they will be just one point behind leaders Ayr with three matches to play.
Grammar are currently in eighth on the same points as Stirling County, who are in the relegation play-off spot and despite an early start this morning they will be up for this one.
Bottom side Boroughmuir are in need of a victory against Dundee HSFP at Meggetland, while the latter head to the Capital in fine form. The hosts have Edinburgh pro Harry Leonard starting at No 10. All games are at 12.30pm.