The Sydney Roosters' winger is expected to miss two to three NRL rounds after suffering a partial MCL tear in his left knee in Saturday's 26-18 win over Manly.

The NRL on Monday ordered an independent assessment of the pitch, to be conducted over the next 24-48 hours.

Morris' knee dug into the surface of the Sea Eagles' rain-soaked home ground, sending a giant divot flying.

The veteran back said he was wary of playing there after injuring his knee at the same venue in 2015 while playing for Canterbury.

Four years ago, Morris jarred his knee after his foot sank into a 10cm pothole. He only missed a week but it resulted in complications and he underwent surgery at the end of the year.

Asked if he was angry, the usually mild-mannered Morris said: "I'd be lying if I said I wasn't.

"If it was the first time it happened to me, I'd just brush it off.

"But I've been to Brookvale twice and my knee's dug in and had an injury as a result.

"As a player, you work so hard week-in and week-out to get out there and, to have this happen as a result of the ground, it is frustrating."

Northern Beaches Council, which operates the ground, has defended the surface, pointing out that several independent assessments had been conducted over the past few months, the last of which was carried out last week and concluded it was in acceptable condition.

The council has also included $1.2 million in its 2019-20 draft budget for a surface upgrade.

"Council is committed to providing as safe a playing surface as possible at Brookvale Oval and has continued to invest around $160,000 each year in its ongoing maintenance," Northern Beaches Council CEO Ray Brownlee said.

Torrential rain hit the ground during the first half and Manly CEO Lyall Gorman said the incident was a result of the downpour - a claim dismissed by Morris.

"The first time I did it, it wasn't raining," Morris said.

Last year, Manly's Curtis Sironen, Kelepi Tanginoa and Lachlan Croker suffered ACL tears at the ground and, in 2017, Sea Eagles winger Jorge Taufua and Canberra's Dunamis Lui suffered ACL injuries in the same round-13 match.

According to statistics provided by the NRL, there were an average of 1.5 injuries per game last year at Lottoland - the third lowest of any ground.

However, the venue was highest in the league for number of games missed per injury with an average of 4.9 matches per injury - followed by Panthers Stadium (4.4) and WIN Stadium (4.3).

NRL officials inspected Lottoland on Monday and reported it was in a reasonable shape and NRL head of football Graham Annesley was not contemplating moving games away.

"If it was the surface which was causing a lot of problems, you'd see it reflected in the other columns as well - it's just not there," Annesley said.

"If the surface was so bad, we'd see many more injuries."

Australian Associated Press