The Jambos keeper produced a number of brave stops to deny Hibernian in Wednesday night's 1-0 Scottish League Cup quarter-final victory at Easter Road.
Now Locke says the former Scotland Under-21 keeper deserves his chance in a full international.
Injured Hull number one Allan McGregor will miss Scotland's friendly encounters with the United States and Norway later this month and Locke believes MacDonald is good enough to deputise.
Speaking ahead of Saturday's Scottish Premiership clash at home to St Johnstone, he said: "We had Jamie MacDonald to thank in those early moments at Easter Road. He has been outstanding this season and Wednesday night was not the first time he has made saves like that.
"I hope he gets the recognition he deserves shortly because he is a fantastic goalkeeper and has really improved over the last two years. Working with Alan Combe has brought him on leaps and bounds.
"I'm delighted for him. He's pulled off as good a save as you will see this season from Scott Robertson to keep us in it.
"Without a shadow of a doubt he is Scotland quality but I am not here to pick the Scotland team. However, if he keeps playing the way he is, I'm sure Gordon Strachan and Jim Stewart will have a look at him."
Locke hopes Hearts' midweek victory against bitter rivals Hibs will work in his side's favour.
Docked 15 points for going into administration and banned from signing new players, the Gorgie manager's young squad let early gains slip by, collecting only one point from their last seven Scottish Premiership games.
Now Locke hopes his rejuvenated side can start the process of chipping away at the 15-point gap separating them from safety all over again at home to St Johnstone on Saturday, where he has a full squad to select from.
He said: "The confidence was a bit low but the only way you will regain that is by winning games. Winning a game of Wednesday's magnitude has had an effect already and you can see the lads are on a crest of a wave.
"The good thing from my point of view is that they are learning all the time. At the start of the season we knew it was going to be difficult and we have made mistakes.
"But the other night at Easter Road showed that when they do concentrate for 90 minutes we are not a bad side.
"I'm not kidding myself. We are a young squad and some of the lads are maybe not ready for this yet but we don't have any other options. We have to put them in and so far they have been fantastic to a man... or a boy."
Chris Millar believes St Johnstone and Hearts will both be buoyed by cup confidence when they clash at Tynecastle.
Midfielder Millar helped the Saints to a 1-0 Scottish League Cup quarter-final win over Morton at Cappielow on Wednesday night.
St Johnstone were paired with Aberdeen in the semi-finals while Hearts, who are 15 points adrift of St Mirren at the bottom of the table, face Inverness, but Millar has turned his focus to the league.
The midfielder said: "It is Hearts on Saturday, we want to kick on now, that's what we want to do to cement our top-six place.
"They will be buoyant, like us, and they always have a fantastic crowd at Tynecastle.
"The fans get right behind the team and they will still believe they can make up the points but we have got to go there and believe we can get a win and try to get a run of wins put together.
"They have been struggling at the bottom of the league, with a young side and with injuries but we have just got to look after ourselves and our confidence will be massive after Wednesday night."
Saints striker Steven MacLean could return from a knee injury if he proves his fitness on his return to full training on Friday.
Frazer Wright serves the second of a three-match league ban and is injured anyway, although an X-ray showed no leg break following the League Cup quarter-final against Morton.
Steven Anderson (dislocated thumb) and David Robertson (ankle) remain on the sidelines.
- Sports & Recreation
- St Johnstone
- Scottish League Cup