Collins was outstanding in steering Monaleen to a first Limerick SFC title in five years last October, kicking six points from full-forward.
Collins, who was first called into the Limerick squad in 2007 and captained the Treaty County in 2011 and 2012, has been absent from the inter-county scene since the summer of 2014.
O’Carroll, meanwhile, last lined out for Limerick during the 2013 qualifier defeat to Longford.
“It is very good news that the two lads are back on the scene,” said Lee.
“They are two fantastic footballers who were out of the equation for a couple of years.
“I don’t know why they stepped back when they did, but from our point of view, it is great to have them back. They bring a lot of experience.
“There are a lot of young lads coming through from the U21s, also. The U21s were very competitive against Kerry in 2016 and very competitive against Cork the previous year. We want to continue their development.”
The manager also revealed that Gearóid Hegarty is to remain with the hurlers in 2017.
Hegarty was midfield for Limerick footballers during the 2015 championship, finishing off that year at wing-back on the all-conquering Limerick U21 hurling team.
He juggled both codes during the respective league campaigns last spring before opting for TJ Ryan’s hurling set-up.
“He is gone hurling for the following year. I spoke with him and we’d a good chat. He wants to stay with the hurling and see what he can get from that. We wish him all the best with that. Obviously, he is going to be a huge loss to us.”