Mark Bentley will miss the start of pre-season training after picking up a groin injury.

The Gillingham midfielder (pictured) could face up to three weeks on the sidelines – missing a vital part of the crucial pre-season period.

"He trained on his own and picked up an injury," said Stimson.

"It’s about what you do and where you do it. There were a good 10 players back training with Danny Ellis (earlier in the week) and none of them are injured.

"Some of the players have decided to train on their own and you can’t argue with them for doing it."

Pre-season will be a vital period for the Gills players and missing too much could prove costly.

"If you miss too much in pre-season it can be hard to catch up," said Stimson.

One player who suffered the same fate last season was Mark McCammon and his season struggled to take off because of it.

"We went away last year and in the first session he picked up an injury," said Stimson.

"He played nowhere near as many games as he or I would have liked and it just shows how important pre-season is."

The players returned for training yesterday (Thursday) and included in the number were Adam Miller and John Nutter – two players who have been working hard to recover from hernia operations.