Locke had two players on the bench who were not fully fit and was still without skipper Danny Wilson following illness.
With midfielder Scott Robinson set to serve a suspension against St Johnstone next week and left-back Kevin McHattie coming off with a hamstring problem, Locke is hoping, but not anticipating, that an appeal to the Scottish Professional Football League to lift their transfer embargo will be successful.
Hearts were automatically placed under the embargo, as well as being hit by a 15-point penalty, when they entered administration and a deal to save the club is still to go through.
Locke, whose side gave Motherwell goalkeeper Gunnar Nielsen some uncomfortable moments throughout the final half-hour, said: "We will just see how Monday goes. It's a lot for 17- and 18-year-old kids to take on. I would love to have a couple of experienced players to help them on the pitch.
"There's Jamie Walker come off there and the early signs are he might have done his metatarsal. So that would be a disaster for us. We will get a scan on Monday and see how it is.
"Kevin McHattie has to come off with a hamstring and if we lose Adam King, we lose another player.
"Today we had Gary Oliver on the bench who has not played for four weeks and probably shouldn't have been there. We had Callum Tapping on the bench when he was only half fit.
"So we are certainly struggling squad-wise. It would be great to get a help but we are in this situation because of the way this place has been run."
King's future is uncertain amid interest from Swansea.
"He's still a Hearts player," Locke said. "Obviously Swansea are keen on him, if there is any news we will let you know."
Motherwell manager Stuart McCall was delighted with the way his side approached the game as they created a series of chances before Sutton rounded Jamie MacDonald and found the net from a tight angle.
The victory secured Motherwell's sixth consecutive top-flight victory - the first time they have achieved that in 77 years.
McCall said: "It wasn't something that was on the forefront of my mind.
"That's five wins away on the bounce. We had an opportunity to do that here a few years ago on Christmas Eve and Hearts beat us 2-0, so I was more aware of that stat. It's all down to the lads in the dressing room, they have bounced back terrifically well."
McCall added: "First and foremost, I thought Hearts' second-half performance shows the spirit is still here. The kids were terrific.
"I'm not saying we should have made it easier for ourselves because MacDonald made two fantastic saves. I was really pleased with the way we played first half."
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- Kevin McHattie