The Galaxy failed to defend their MLS Cup crown in a trophy-less 2015 campaign, finishing fifth out of 10 sides in the Western Conference and losing out to Seattle Sounders in the first round of the play-offs.
Former England midfielder Gerrard scored two goals in 15 appearances in all competitions following his move from Liverpool and Donovan believes Gerrard is one of a number of high-profile foreign players to have found the league difficult during their first year.
"I think David Beckham went through it too when he first came. For most people the league is more difficult than they think.
"It is not necessarily better quality than where they come from but it is a very fast-paced, physical league. When you couple the travelling and the heat and different things, it makes it difficult.
"Robbie Keane was a bit of an anomaly – he fitted in straight away and didn't seem to miss a beat.
"But I think Gerrard has enjoyed it and will come back next year much better."
Asked if the recent arrivals of the likes of Gerrard, Frank Lampard and David Villa were making an impact in the quality and interest levels in MLS, Donovan said it was part of a gradual process of improvement for the league.
The 33-year-old added: "Yeah, I am noticing a difference, but it takes time to build history, passion and a fan base.
"We don't have the hundreds of years of experience and passion for it, but we are getting there."