WESTS TIGERS coach Tim Sheens has plucked 19-year-old Robert Lui from the club's Toyota Cup side to make his first-grade debut as the Tigers bid to stretch their winning streak to six games, against Cronulla at Toyota Stadium on Sunday.

Lui, who has been playing five-eighth in the under-20s, will come in at halfback, with Tim Moltzen switching from halfback to fullback for Shannon Gallant, who will need the Tigers to make the finals if he is to be any chance of playing again this season.

Gallant is out for five or six weeks because of a broken fibula sustained in last weekend's win over Sydney Roosters. The Tigers have charged into seventh place after five straight wins.

South Sydney coach Jason Taylor has moved David Fa'alogo from lock to prop in place of captain Roy Asotasi, who is out for the rest of the season after tearing the anterior cruciate ligament in his knee, and made prop Luke Stuart skipper for the game against Gold Coast at ANZ Stadium on Friday night.

Queensland representative Michael Crocker, who has been on the bench recently, will start at lock for the Rabbitohs.

Elsewhere, Bulldogs prop Ben Hannant is expected to miss two or three games because of a torn popliteus muscle behind his knee sustained in last weekend's win over Canberra.

Bulldogs coach Kevin Moore has promoted Jarrad Hickey to the starting side in the Queensland Origin prop's place for the game against North Queensland at Dairy Farmers Stadium on Friday night, with Brad Morrin coming on to the bench.

''It's not the end of the world, not an anterior cruciate ligament or anything like that,'' Moore said. ''And Ben's a quick healer, so the aim will be for him to get at least one game in before the finals, and with a bit of luck two.''

Moore felt the Bulldogs were developing nicely in the run-in to the finals, saying: ''We're probably not in peak form, but we're not far off it. The loss to Parramatta was disappointing, but when you look at what they've done recently, you'd have to rate them one of the form teams in the competition.

''We're coming along fine, and as long as we have reasonable luck with injuries, I'm confident we'll be firing come finals time.''

Cowboys coach Neil Henry has named lock Luke O'Donnell and centre Ashley Graham for returns from injury, but they still have to prove themselves ready at training this week. Henry has named a six-man bench in case one or both of them don't come through.

Manly coach Des Hasler has picked Kieran Foran in the troublesome five-eighth spot for Saturday's game against Sydney Roosters at the SFS. Jamie Lyon and Chris Bailey are others who have been used there this season.

Hasler needs to find an answer in a hurry to the woes that caused the Sea Eagles to lose two games in a row and fall back into the desperate battle just to make the top eight, when a couple of weeks ago they were in fifth place with a top-four spot and home game in the first week of the finals within reach.

Tim Mannah will start in place of injured prop and captain Nathan Cayless for Parramatta against the Warriors at Parramatta Stadium on Saturday. Cayless is out with a calf injury suffered in last weekend's win over Newcastle. Second-rower Nathan Hindmarsh will take over the captaincy.

Warriors prop and captain Steve Price remains out with a rib injury, but star fullback Wade McKinnon has been reinstated after being stood down for one game as a disciplinary measure for missing a team recovery session.

And Dane Nielsen has been slotted in to replace superstar Greg Inglis for Melbourne against Newcastle at EnergyAustralia Stadium on Monday. Inglis has been stood down by the club because he is facing assault charges following an incident involving his girlfriend.