Pettine told the Cleveland Plain Dealer on Monday he visited Manziel last month and said "there was no set day" to how long the quarterback would remain in rehab when he entered the program. Manziel has been in rehab five weeks, longer than the 28-day minimum typically associated with such programs.
"It's more important -- the personal stuff now -- football is an afterthought so we're just giving him his privacy and [letting him] do what he has to do," Pettine told the newspaper. "It's something that he was very resolute that needed to get done and again, I'll respect his privacy and leave it at that."
Manziel, a star quarterback at Texas A&M who was drafted 22nd overall by the Browns in 2014, has been criticized for his partying lifestyle reputation. In the past, he has posted photos of himself on Twitter and Instagram drinking at parties.
Manziel, 22, appeared in five games for the Browns last season, passing for 175 yards. Despite the lackluster season and off-field issues, Pettine said he hasn't given up on Manziel.
"We've touched base a handful of times, and I'm just looking forward to kind of seeing him on the other side," Pettine said Monday on WKNR-AM in Cleveland.
With Browns starting quarterback Brian Hoyer reportedly set to sign with the Houston Texans after the start of the NFL free agency period on Tuesday, Manziel is expected to battle for the Browns' starting quarterback job this season.