And the director of rugby already has cover in mind with former London Irish back row forward Jon Fisher having impressed during a trial period at Franklin’s Gardens.
Dickinson picked up the problem at the end of last season, with blockbusting performances in the successful double bid taking their toll.
He will now miss the start of the new campaign, meaning Saints could offer Fisher a chance.
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And Mallinder said: “With Sam Dickinson and his injury, it is an area we do need to look at. It’s a shame Sam’s injured, he got it at the end of last season and didn’t recover from it.
“He’s had an operation and will be out for three months.
“It’s disappointing for Sam because I thought he was awesome last season and some of his ball carrying was unbelievable, but he’ll be back, which is good.”
Fisher played 40 minutes in last Saturday’s 33-28 victory against Championship side Rotherham Titans.
Mallinder has been happy with how the 25-year-old has fitted in and will hand him another opportunity to make an impression in this weekend’s friendlies against Leinster and Moseley.
“Jon’s come in here, he’s got his head down, trained very, very well,” said the Saints boss. “We’ve just seen him play 40 minutes at the weekend, but he made a very good impression.
“I’ve watched him again this week, he’s looked good in training and I’m really looking forward to seeing him on Saturday.”