FORMER Collingwood captain Nick Maxwell's ankle sprain was the most significant injury to come out of a relatively uneventful round 17.

Maxwell suffered a nasty eversion mechanism sprain of his left ankle last Sunday against the Bombers, an injury that involves a longer recovery period than your typical sprain.   

Last Sunday, Maxwell was playing his first senior game after a five-week layoff with a calf injury.

That game against Essendon proved to be his last with the former skipper announcing his immediate retirement on Wednesday afternoon due to the injury. 

Let's look now at the players in doubt for this weekend's games in round 18's split fixture.

Unfortunately for North Melbourne fans, I'm expecting Roos vice-captain Jack Ziebell will miss this Friday night's clash with Carlton.

Ziebell has missed North's past two games with a right knee injury he suffered in round 15 against the Brisbane Lions.

The midfielder still has some soreness in the knee and I suspect the Roos will rest Ziebell with a view to him returning after their bye next weekend.

Ziebell's teammate Lachlan Hansen is also in doubt after the key defender was one of three players to suffer concussion last weekend.

Given Hansen's history of concussions, North Melbourne will be conservative with him, delaying a decision on his availability under later this week.

Hansen will undergo the usual concussion tests this week according to AFL protocols.

However, given North will enter Friday night's game off a six-day break, time is against Hansen's bid to prove he has fully recovered.

Port Adelaide's Robbie Gray and Richmond's Reece Conca were the other players to suffer significant head knocks last weekend.

Reece Conca is helped from the field during the Tigers' clash with Port. Picture: AFL Media




Gray was concussed late in Port's loss to Richmond last Sunday and, given the Power are playing Melbourne at the Adelaide Oval this Sunday, he, like Hansen, faces a race against time to prove he has fully recovered.

Port Adelaide medical staff will require him to pass repeat concussion testing later in week.

Conca was involved in a heavy collision in the third quarter of the same game and had to be stretchered from the ground. But with Richmond having the bye this weekend, I expect he should be right to take on West Coast on Friday week.

Getting back to Friday night's game, Carlton is likely to regain forward Troy Menzel, who injured his AC joint in round 16 and missed last Saturday's game against the Sydney Swans.

Menzel is listed as a test this week and I think he will probably play against the Roos.

However, the Blues announced this week that Andrew Walker's season is over. The defender has been carrying a chronic knee injury and pulled up particularly sore after the Blues' loss to the Swans.

Walker will undergo an arthroscopy this week, which will give him the best opportunity to be ready for the 2015 season, although he might still have ongoing concerns with his knee.

Like teammate Robbie Gray, Port forward Angus Monfries is in doubt for this Sunday's clash against Melbourne.

Monfries missed last Sunday's loss to Richmond with a recurrence of his hamstring injury and, although the Power are hoping he can do some light training this week, I doubt they will risk him against the Demons, especially when they have a bye next weekend.

Likewise, I don't expect Fremantle will risk defender Luke McPharlin against St Kilda this Saturday.

McPharlin had been coming back from a knee injury and then sustained a calf injury at training ahead of last Sunday's win over Greater Western Sydney.

Calf injuries have dogged the Freo veteran over the past 12 months, so the Dockers will be conservative with him and I don't expect he will be available until after their bye next weekend.

Essendon defender Michael Hibberd has been out of action for the past two weeks with a sprained ankle and tight hamstring, but should be available to play this Sunday against the Western Bulldogs.

Western Bulldog Adam Cooney is returning from a left hamstring injury suffered in round 13 and is listed as a test this week.

The 2008 Brownlow medallist has had four weeks of rehabilitation and provided he undergoes a full training week with no setbacks he's likely to be available for selection.

Fellow Bulldog Tory Dickson is also listed as a test this week, as he gets closer to a return from the torn pectoral tendon he suffered in round eight. This is ahead of expectation as round 20 was the initial realistic return date prediction.

Looking ahead to next weekend's games, the Sydney Swans should welcome back star pair Kurt Tippett and Dan Hannebery for the big clash with Hawthorn next Saturday night.

Tippett, who was coming off an arthroscopy of his knee, has missed the Swans' past two games after developing bone bruising in his knee. However, he should be available for selection after the Swans' bye this weekend.

Hannebery is recovering from a significant syndesmosis injury to his right ankle, which is similar to Maxwell's injury.

Hannebery has been sidelined for the past month. He was keen to play last Saturday night, but the Swans held him back and I expect he'll be right to take on the Hawks.

Adelaide pair Scott Thompson and Josh Jenkins should both be fit for the Crows' clash with Collingwood on Sunday week.

Thompson went into last Friday's loss to Hawthorn with a slight doubt over his left hamstring and was subbed out late in the game after experiencing further soreness.

This was not a major setback, however, and with the bye giving Thompson an extra week to recover I expect him to play against the Pies.

Jenkins rolled an ankle in the Hawks loss and wasn't walking all that well by the end of the match, but he, too, should be right to play after the bye.

Collingwood forward Jamie Elliott has been undergoing the normal rehabilitation for a low-grade hamstring injury and is another player who should be able to use this weekend's bye to his advantage. I'm expecting him to be available to take on the Crows.

Gold Coast's recent run of soft injuries continued last Saturday, with Kade Kolodjashnij suffering a right hamstring injury late in the loss to the Western Bulldogs.

Kolodjashnij will now undergo rehabilitation over a 3-4 week period before returning to the field.

With just six rounds remaining until the finals, the race is on for players with long-term injuries to get back in time for September.

Two such players are Essendon captain Jobe Watson and Hawthorn defender Josh Gibson.

Watson tore his hip flexor tendon, or rectus femoris, in round 12 and following a surgical repair his recovery is on schedule.

He's entering a phase now where he's increasing the intensity of his training after the repair of the tendon, but Essendon won't want to load him up with heavy sprinting or kicking work too soon.

Rectus femoris repairs are so rare in footy and we're entering new territory with the procedure being performed during a season, so it's very hard to accurately predict Watson's return date.

When he suffered his injury, the most optimistic estimate was that he would be back in 10 weeks, which would see him return in round 22.

That remains possible, but 14 weeks is probably a more realistic recovery period. Of course, by that time the Bombers' finals campaign – if they make the top eight – could be over.

Gibson ruptured his pectoralis major tendon in round eight and, like Watson, has been making steady progress in his rehabilitation.

However, like Watson's injury, it has been extremely rare for AFL players to have full pec repairs and then return in the same season.

Remarkably, we have had four cases so far in the 2014 season – Gibson, Dickson, Joel Tippett and Matt Rosa. This may reflect changes in tackling techniques and tendon fatigue from weight sessions.

Generally, pec tendon injuries involve a similar recovery timeframe to hamstring tendon repairs: 10-12 weeks.

Gibson has now been out for 10 weeks. His training has stepped up, but he's still at a vulnerable time for re-injurying the tendon.

By round 20, he will have been out for a full 12 weeks and that looks to be the earliest he could return.