CLEVELAND (AP) -- Alex Mack is still floating in free-agency limbo, but the Browns remain confident the Pro Bowl center will land back with them.
Mack visited the Jacksonville Jaguars last weekend, and a person familiar with the situation told The Associated Press the sides are working on an offer sheet. The person spoke Wednesday on condition of anonymity because of the ongoing negotiations.
The Browns, who placed a transition tag on Mack, would have five days to match any offer, and owner Jimmy Haslam said the team wants to keep him at all costs.
''We remain optimistic that Alex Mack will be a Cleveland Brown for a long time,'' Haslam said Tuesday night at the premiere of ''Draft Day,'' a fictional film about the Browns. ''We want him to be. I think we've made it very clear that he's the kind of person, the kind of player we want in our organization.''
The Jaguars are looking to revamp what was one of the league's worst offensive lines in 2013. They drafted left tackle Luke Joeckel with the second overall pick in last year's draft and signed former Denver Broncos guard Zane Beadles in free agency last month. Longtime center Brad Meester retired in January after 14 seasons.
Jaguars general manager Dave Caldwell said last month that signing Mack to an offer sheet would be ''a little dicey.'' But he and coach Gus Bradley clearly would like to add Mack, who's considered one of the best centers in the league.
It's unclear how quickly an offer might happen.
As Mack tests free agency, he has missed the initial days of the Browns' offseason program under first-year coach Mike Pettine.
During a conference call Wednesday, Pettine addressed Mack's current displacement from the Browns.
''It's a situation that's very fluid,'' he said. ''I'm not that comfortable talking about it because it's an ongoing contractual thing. But I just think that any time you're in a situation where's there a tag and I just think guys feel like, 'Hey, nothing has happened so far,' so there might be some optimism there, but it's something that's very fluid and changes day to day.''
Pettine would not comment on whether the Browns were in negotiations on a long-term deal with Mack, who has not missed a single offensive snap since he was drafted by Cleveland in 2009.
Although Mack is not in attendance for this week's workouts, Pettine doesn't think his absence is cause of concern.
''I think it's important, but I don't think it's critical,'' he said. ''I think he's certainly smart enough that he will be able to - if we do get him on campus - he will be able to make up for that lost time.''
Mack has until July to sign a one-year, $10 million contract with the Browns.
The Browns don't want to lose Mack and in the days leading into free agency, Haslam and Pettine were both part of a traveling party that went to California to see him.
Asked if the Browns are prepared to match any offer Jacksonville might make to Mack, Haslam smiled.
''We want Alex to be a Cleveland Brown,'' he said.
So do his teammates, and Pro Bowl tackle Joe Thomas seemed most confident he'll be playing alongside Mack again.
''There's no doubt that he'll be here at least this year,'' Thomas said. ''I think that's for certain. I certainly hope we can sign him to a long-term deal and keep him here for much longer than I am here.''
AP Sports Writer Mark Long in Augusta, Ga., contributed to this report.