Mackall, who started the first seven games this season after being a reserve linebacker as a freshman, said that a "disagreement" with Edsall stemming from a meeting over academic issues played a role in his decision to leave the football program.
Mackall joins 13 of former coach Ralph Friedgen's players with eligibility remaining who left before the season began. It's not certain how many others may also leave as part of the ongoing transition. A team meeting was scheduled for Sunday night.
The Terps finished a dismal 2-10 season — their second with that record in the past three years— with a 56-41 loss at North Carolina State Saturday, a game which Maryland led 41-14 . It was the second largest comeback in ACC history and a school-record seventh straight double-digit defeat.
Mackall said that he received his release "immediately" after requesting it last Monday. Mackall would not get into the specifics of the conflict that resulted in Edsall announcing that he was suspending the former Edmondson High star. Edsall did not give reasons for the suspension except to say that Mackall had broken team rules.
Asked for his impression of Edsall's first season in College Park, Mackall said, "Basically how the season looked from everyone else's perspective. It's been miserable. When you're not winning, that's how it's going to be."
Mackall would not say whether any other players were going to leave, but added, "I know the program as a whole, many of the players weren't too happy, it wasn't really the family vibe that we had a year ago."
A key figure for next season could be quarterback Danny O'Brien. O'Brien, the Atlantic Coast Conference rookie of the year in 2010, had a difficult season that ended when he broke his left arm in the season's 10th game against Notre Dame.
The quarterback has not made any pronouncements about leaving or staying, nor has he complained to Edsall about the program in general or the offensive system in particular. Maryland had new offensive and defensive coordinators this season.
"Danny's plan is to focus on getting his arm healthy and on spring ball at the University of Maryland," Matt O'Brien, the quarterback's father, said Sunday.
After completing 31 of 44 passes for 348 yards and a touchdown in a season-opening win over Miami — Maryland's only victory against a Football Bowl Subdivision team all season — O'Brien's problems began when Edsall suspended starting receivers Ronnie Tyler and Quintin McCree two days before the next game against West Virginia. O'Brien threw a costly interception that halted a second half comeback against the Mountaineers at Byrd Stadium.
Some of Edsall's problems inside the team also began after those suspensions, according to Mackall. Mackall said that players were not pleased with how Edsall spoke publicly about the way Friedgen ran the program. Friedgen was fired last January, after leading the Terps back from a 2-10 season to finish 9-4 and going to the team's seventh bowl game in 10 years. Friedgen was named the ACC coach of the year.
Edsall said at the time that there had been little, if any, accountability by the players prior to his arrival last January.
Aside from upsetting many former players and Friedgen supporters, it also caused issues with the current players, Mackall said.
"It wasn't the truth at all," Mackall said. "Under Coach Friedgen, everybody was accountable. The whole situation about academics, I've got my own thoughts of why things happened, I don't want to say too much about that. Coach Friedgen held everyone accountable for their mistakes and actions."
The NCAA stripped Maryland of three football scholarships because of poor academic performance under Friedgen, particularly during the 2009 season.
Mackall, who finished the season with 30 tackles, including three sacks, in eight games, said the tipping point for him in terms of his feelings abut Edsall came after the Florida State game, a 41-16 loss to the Seminoles Oct. 22.
"After the Florida State game, he said that we didn't have enough talent, that we didn't have enough players to compete with teams like Florida State and Clemson," Mackall said. "He pretty much lost me because any coach is expected to stick with their soldiers in the middle of battle. I felt like he really wasn't focused on us or the task at hand by that comment."
Mackall said that he hasn't made a decision as to where he will continue his college football career. He would have to sit out a year if he transferred to another FBS school, but could play immediately if he decided to go to a Football Championship Subdivision school.
Mackall confirmed that he has stayed in touch with Terrance West, the freshman tailback from Baltimore (Northwestern) who has been instrumental in leading Towson's turnaround from a 1-10 team last season to a 9-2 team this season. Mackall said he has thought about the Tigers "a little bit" and would likely make a decision in the next "couple of weeks."
Dante Jones, who coached Mackall at Edmondson and is helping his former player in choosing another school, said that Maryland "wasn't really where he wanted to be from the beginning" but ended up there after spending half a year at Fork Union Military Academy in Virginia.
Jones said that Edsall's coaching style was not the only reason for Mackall's unhappiness.
"When you're in a situation when you're not happy, anything can make it more," Jones said. "It was just time to move on."
Baltimore Sun reporter Jeff Barker contributed to this story.