Jacobs made his first appearance in 17 months when he came off the bench during extra time as Livi beat St Mirren in the Premier Sports Cup last weekend.
The 31-year-old suffered a foot injury in Livingston' s final match before the pandemic stopped Scottish football and had some false dawns as he attempted to return last season.
His comeback appeared some way off even earlier this month, but other selection issues saw Jacobs put on the bench for the cup tie, and an injury to left-back Jackson Longridge gave the long-serving midfielder a welcome return.
Martindale said: "To be honest, I was looking about and I never really had anyone in the left-back area as Jacko took a sore one to his knee.
"It was probably a bit early for Keaghs to be honest, but I say to the physio every time, 'just put him on the bench, I'll not use him'. Generally, what I do is, I use them.
"Keaghs is tried and trusted, he has been here that long. So I know what Keaghs brings to the squad and I know what he can bring to me on a match day and I trust him implicitly.
"He is genuinely one of these players that I can play anywhere. Anywhere bar striker and centre-half.
"He is one of these boys that can't train at 70 per cent, he can't ease his way back in. He is 100 per cent or nothing. So he generally comes back from his rehab in good condition because he puts so much work into it. He trains at 100 per cent every training session."