Sunseri, a junior, was sixth on the team with 20 tackles coming into Saturday's game against Arkansas. He injured the knee covering a kickoff in the first half. He led the team with four pass breakups and two interceptions, both of which he returned for touchdowns.
"Vinnie has done a great job for us," Saban said. "He's an outstanding player and a very good person, a good leader. You can't say enough about the job he's done throughout the year and in his career.
"I always hate it when guys get injuries. It's a tough part of the game."
Sunseri, who may to be able to resume activity in four months, is eligible to enter the 2014 NFL draft.
Alabama has had to deal with much turnover in the secondary this season. Veteran safety Nick Perry was lost for the year with a shoulder injury late last month and starting free safety Ha Ha Clinton-Dix was suspended two games for violation of team rules. John Fulton started at cornerback at the beginning of the year before giving way to true freshman Eddie Jackson, who has since missed time with an injury. Bradley Sylve, a third-year sophomore, injured his ankle against Arkansas.
"Landon has been a very good player for us in whatever role we ask him to play," Saban said. "... Strong safety is his natural position. When we had all of our players, he was Vinnie's backup, so that's where he got the majority of his reps."
Collins, a five-star prospect coming out of high school, filled in for Sunseri for much of the game against Arkansas. He had filled in for Clinton-Dix at free safety the previous two weeks.
"Great leader," Collins said of Sunseri. "I looked up to him. He's helped me out at free safety with the calls and getting me to settle down. He's going to be missed."
Joe Schad of ESPN contributed to this report.