Lockhart has made 157 appearances for Scotland
Scotland visit Hampshire and Kent looking to build on a promising start to their Clydesdale Bank 40 campaign.
The Scots have won one and lost two but head coach Peter Steindl has been heartened by the start made by his men.
"We set our stall out to improve with every game this season and we feel that we've done well in two out of three games so far," he told BBC Scotland.
Dougie Lockhart and Gregor Maiden have been recalled, with Ryan Watson unavailable and Marc Petrie rested.
Watson is unavailable for the trip because of business commitments, while Lockhart will take over wicket-keeping duties from Petrie.
Matthew Parker is being allowed to play club cricket after being twelfth man in the first three games.
"It's a shame Ryan isn't available, he's been hitting the ball well but, at the same time, Gregor Maiden has been doing well in club cricket," added Steindl.
"We also welcome back the experience of Dougie Lockhart, who has been in good form."
The Saltires, who play Hampshire on Sunday and Kent on Monday, opened their campaign with a win in Lancashire but lost to Kent and Nottinghamshire last weekend.
Gavin Hamilton (captain), Omer Hussain, George Bailey, Freddie Coleman, Richie Berrington, Gregor Maiden, Neil McCallum, Dougie Lockhart (w/k), Gordon Drummond, Majid Haq, Ross Lyons, Gordon Goudie, Neil Laidlaw.