Mack said he had to go to Wikipedia to see what the transition tag meant.
"I think everyone had to go to Wikipedia to see what that was," he said. "I’m relieved it’s behind me. The uncertainty where you’re going to be is there and now it’s behind me."
He was asked why he wanted to have an opt-out clause after two seasons. If he doesn’t opt out, he will receive $8 million guaranteed.
"It gives me a lot of power as a player, which is exciting," he said. "It’s something that might happen and it might not. Two years is a long time away."
During the negotiations, reports came out that Mack wasn’t interested in returning to the Browns, something he says was untrue. Mack never said he didn’t want to return to the Browns.
"Something that is real important to know is there’s a business side (to the NFL)," Mack said. "I have an agent. Stories come out. Business is business. It’s positioning.
"I’m a football player and all I can say is I’m excited to be here and play football and ready to work," he said. "That’s why I hire an agent. I’m not an agent. I’m a football player and am really happy the way it worked out."
Reports said that Mack was tired of the losing and was upset with the firing of Rob Chudzinski, along with his offensive line coach George Warhop.
"You don’t want to see change and turmoil going on," Mack said. "Jimmy Haslam did a great job and took some heat for making moves, but it shows he cares. That’s exciting and a good way to look at things.
Mack admitted the trip that Haslam, Ray Farmer, Mike Pettine and others made to visit him in California before free agency was impressive.
"It was a really good trip," he said. "They came out and to have them all show up and bring a real strong front. I was excited of where this team was going, but at the same time, there was still the business side of things."
Mack was asked why he’s optimistic the Browns will turn things around.
"I think we have a really good core group of guys," he said. "We had a good group of guys last year and a lot of real tight games and to think about how close you were and to build upon that for this year, I’m excited.
"I know the players that are on this team," Mack said. " I know the talent on the team last year. We were close and then to think about that and with the new coach and came out with a really good visit and a really good plan.
"They knew what they were talking about and had a lot of fire. They upgraded the offense and I like where this offense is going."
Mack said ultimately he wants to win. The Browns have not won more than five games since Mack joined the team in 2009.
"I want to win games," he said. "I’m here to work hard and win games."
Mack took part in the Browns offseason program Monday and is ready to get set for the 2014 season.
"I was here today working out," he said. "I have an offense to learn and I want to hang out with my teammates."
With the signing, Mack is now the highest-paid center in the NFL. He was asked if that was a big deal to him.
"I would say yes," he said. "I work hard and am going to continue to work hard and I am excited to be a Brown."