McLean, who won the 2017 NRL title at Melbourne, will mark the milestone in the clash with the Dolphins at Suncorp Stadium on Friday night.
McLean is at the pointy end of negotiations with the Cowboys for a new deal.
"I am optimistic," Payten said when asked whether the 31-year-old would remain at the club.
"You can never say one hundred per cent certain but I know how settled he is and I know what he means to the club.
"We want to have him. Discussions are positive. It is going back and forth and we expect something to eventuate soon.
"Macca is our forward leader in the middle and really cares about the place."
The Cowboys are in ninth position on 28 points and will need to win against the Dolphins and Penrith (away) in their remaining games to play finals.
They are without injured Queensland second-rower Jeremiah Nanai (shoulder) and winger Semi Valemei (knee) from last week's 32-12 loss to Cronulla.
Heilum Luki will start in place of Nanai while Zac Laybutt has been called into the side at centre for just his third NRL game. Murray Taulagi will shift back to the wing to accommodate Laybutt.
"The players are really excited to have Zac in the team again and Heilum has had a stop-start year (due to injury) and we all want him to get some continuity this week," Payten said.
"(Laybutt) doesn't say a lot but what the players admire about him is that he is a fair footballer and quite natural. He can play quite a number of positions."
Payten is often asked about the loss of former outside back Hamiso Tabuai-Fidow to the Dolphins this year to play his favoured No.1 position.
The Cowboys backed Scott Drinkwater instead at fullback and he has been one of the NRL's best. The pair will go head to head on Friday night.
"There are a lot of factors that go into that decision," Payten said.
"(Tabuai-Fidow) came to us to ask for (a release and) an opportunity to play in his preferred position.
"There is the salary cap that comes into it and to be fair Drinky has cemented that fullback spot and been our best player."
Centre Peta Hiku will also play his 200th NRL game in Friday's match.
"He is a competitor on the edge and is a really smart footballer. He has brought to the club a level of calmness and a competitive nature that drives a lot of our training," Payten said.
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