CARLTON is sweating on the fitness of midfielder Patrick Cripps after he suffered a game-ending calf injury midway through the second quarter against Melbourne.

The 22-year-old attempted to smother Jayden Hunt, only to receive a direct kick to the top of his left calf as the Demons' defender tried to get boot to ball.

Cripps walked off the ground in the hands of trainers and was taken into the rooms, before emerging midway through the third term on crutches with his leg taped.

The Blues were reduced to two men on the bench just before half-time when defender Simon White picked up a knock to his already strapped left knee.

The 29-year-old immediately grabbed his knee and hobbled to the rooms, joining Cripps on the bench in the second half with his leg wrapped in ice.

Fremantle defender Tom Sheridan injured his left hamstring chasing a North Melbourne opponent before half time and did not return to the field.

"It doesn't seem like a tendon (injury), it seems like a standard 21-day hamstring," Dockers coach Ross Lyon said of Sheridan's early prognosis.

The Dockers have two other injury concerns ahead of Sunday's Western Derby at Domain Stadium, with defender Joel Hamling and utility Brady Grey restricted by hip and shoulder issues respectively.

Hamling hurt his right hip when he collided into Kangaroos forward Ben Brown in a marking contest and required treatment over the course of the game.

Grey, meanwhile, injured his already strapped left shoulder as he tried to smother former North captain Andrew Swallow in the third term.

The 21-year-old had his shoulder re-strapped in the rooms at three-quarter time and featured in the last term.

Richmond defender Dylan Grimes was forced to sit out the second half against St Kilda due to concussion he suffered in a marking contest before half-time.

The 25-year-old went back with the flight and was collected late in the head by St Kilda forward Tim Membrey's elbow.

Grimes remained on the ground and sported a nasty bruise below his left eye almost immediately after the incident.

He was assessed during the main break and failed a concussion test.

Greater Western Sydney defender Nick Haynes needed attention for a knock he received to his left knee in a contest with Hawks defender Taylor Duryea late in the third quarter.

Haynes performed a mini fitness test at three-quarter time and played on, although he was limping heavily towards the end of the game but waved away the trainer.

Giants midfielder Josh Kelly received a knock to his right shin/ankle as Hawk Isaac Smith crashed through his tackle in the final quarter.

Kelly was hobbling at the interchange area but got through the game, kicking a critical goal late in the piece.

Brisbane Lions forward Josh Walker came off the ground after receiving a knock to his right calf in a marking contest midway through the first quarter against Geelong.

The 24-year-old former Cat had his lower leg strapped and tried to perform run-throughs along the boundary, but was clearly hindered by the injury and sat out the rest of the game.

Adelaide captain Taylor Walker received an inadvertent elbow to his right eye from Western Bulldogs defender Dale Morris in a marking contest late on Friday night.

The 27-year-old spent the closing minutes on the bench and had a noticeable bruise around his eye in the rooms post-match.

Sydney midfielder Zak Jones limped off in the first minute of the game with a corked left leg he suffered in a knock from Gold Coast captain Tom Lynch, but the Swan ran it out along the boundary line and returned.

With the result beyond doubt, Jones sat out the last 10 minutes of game time with ice on his left leg following the earlier injury.

Swans forward Sam Reid was also icing his leg on the bench late in the game.

Essendon midfielder Zach Merrett came off the ground in the third quarter after being clipped with an elbow to the chin from Magpies onballer Levi Greenwood.

The Bombers remonstrated with Greenwood after the incident.

Merrett went down to the rooms for a concussion assessment and resumed in the latter part of the third term.

In other injury concerns in round 16:

- Port Adelaide midfielder Sam Powell-Pepper was assessed during the second quarter against West Coast for a shoulder issue, but returned to the field. Power coach Ken Hinkley said the youngster was certain to play in Saturday's clash with North Melbourne.

- St Kilda ruckman Billy Longer went down early in the first term against Richmond with a corked right thigh, but he had his leg strapped and returned later in the quarter. Saints coach Alan Richardson was "optimistic" Longer would be available for selection against Essendon on Friday night.

- Sydney captain Josh Kennedy was a late out against Gold Coast due to quad tightness.

- Collingwood defender Jeremy Howe was a late withdrawal against Essendon with calf tightness.

- Gold Coast defender Sean Lemmens copped a blood nose in the third quarter when his face was driven into the ground in a contest with Swan Dean Towers. Lemmens returned with a large bandage across his nose.

- Essendon defender Michael Hartley picked up a corked left thigh in a marking contest with Magpie Ben Reid during the second quarter. Hartley, who entered the game with his left knee taped, had his leg strapped before half-time.

- St Kilda defender Daniel McKenzie was winded in the closing minute against Richmond when he flew for a mark and landed heavily on his back.

- Sydney forward Lance Franklin had his right wrist taped during the second term against Gold Coast, but he did not appear to be affected by the complaint.

- Hawthorn wingman Isaac Smith received treatment on his right hip during the third quarter against Greater Western Sydney, but finished the game.

- Collingwood defender Lynden Dunn shook off an accidental poke to his left eye he received from Bomber Cale Hooker in a tackle early in the game.

- Adelaide small defender Luke Brown hurt his right knee in the second quarter as he applied tackling pressure on Western Bulldog Clay Smith. Brown limped off and had a knee stability test at the interchange area before being given the all clear to resume before half-time.

- Crows midfielder Rory Sloane ended the game against the Bulldogs with ice wrapped around his right calf.