The former Manchester United midfielder spent last season on loan at Championship side Birmingham, an experience that he believes helped him progress.
And now the 20-year-old has targeted a spot in the Sam Allardyce's starting line-up.
"Pre-season has been good and I've enjoyed the whole trip so far. I've just enjoyed the work and the whole group has done well," he told the club's official website.
"Hopefully I can get an opportunity. I've just got to carry on working hard in pre-season and show the manager what I can do."
Morrison made 30 appearances in all competitions at St Andrew's, scoring three goals, but he is now keen to prove his worth to the east London side in the Premier League.He added: "It was really good. I think I needed the year out and I think it went well, because I enjoyed my year at Birmingham a lot.
"I missed West Ham a lot but it was still good in the Championship.
"It was different to the Premier League, obviously, but it was a good challenge. Lee Clark is a great manager and he helped me through a lot. He talked me through my rights and wrongs and he helped me through the season.
"I probably enjoyed the game against Millwall the most, when we came back from 3-0 down to draw 3-3. That was probably the best game because the whole team worked hard. I also scored a couple of good goals."