The Lions boss oversaw a major overhaul last summer and has already set about getting some of his recruitment done early to ensure there is no repeat this time.
With Forrest set to depart under freedom of contract and Odin Bailey due to return to Birmingham after his loan, Martindale already has a good idea of how next term's squad will look.
"I've definitely got an eye on next season," said the Lions boss. "Probably 95 per cent of my perceived starting XI will still be here next season but it's no secret that Alan's probably not going to be here and Odin Bailey will return to Birmingham.
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"Last year I had a busy summer because I lost my goalie coach, my assistant manager and 15 players. I was looking for quality and quantity, which is very difficult.
"I can't say too much because I'm still waiting to get them all passed off and signed, but I've actually got three boys coming on pre-contracts.
“After that, I'm probably looking for another four players with quality in offensive positions but I can take my time with those positions. We're looking for quality but I think I've got the time to do it, whereas last year it felt a little bit rushed at times."
Martindale is planning to sign more players from overseas this summer. "I've tweaked my recruitment slightly this year," he said. "Last year I based it solely on the UK, albeit Stephane Omeonga came in late on.
"This year I've looked further afield for players so I'm really looking forward to putting a good bit of time and detail into looking at players."
Martindale admits 25-year-old winger Forrest, who has been heavily linked with Hearts and Dundee United, is unlikely to be at the Lions next term.
"I'm resigned to Alan going," he said. "There are a couple of clubs in for him.
"I've given him my thoughts on it and obviously I'd love to keep him here but I'm realistic enough to know when a big club comes calling and there's the financial rewards and you're getting a chance to play at a fantastic stadium with great training facilities.
"You've sometimes got to shake the player's hand and move him on. I don't think he's made up his mind 100 per cent but I'm pretty sure he won't be playing for Livingston next year."