The Magpies travel to the London Stadium chasing their third Premier League victory in a row following consecutive 2-0 victories over Huddersfield and Burnley at St. James' Park.
Despite Clark and Elliot remaining sidelined for the clash in East London, Benítez has no other injury concerns whilst revealing Shelvey's request to feature for United's second string against Fulham in order to gain match fitness.
Benítez said: "Jonjo Shelvey has asked to play today for the under-23s, so he will play with the under-23s (against Fulham) tonight. It means he’s pushing in the right direction. Clark and Elliot are out (of Saturday's game) but the others are available.”
The Hammers occupy tenth place on 36 points, five points ahead of the Magpies, and whilst United aim to build on their positive run, the manager stressed the importance of approaching each fixture with great attention.
Newcastle suffered a 3-0 defeat to Manuel Pellegrini's side back in December after achieving three successive league wins and Benítez is determined for United to learn from their experiences.
“My message to the players, and everyone, is that we still have a lot of work to do. We have to stay calm and have to approach every game with the same idea we had from day one. The next game is the most important and if we can get to 38 or 40 points, we can enjoy it a bit more if possible.
"We can see the future that we have along with the other teams around us. However, that means nothing because three or four weeks ago, we were thinking it would be very difficult.
"Now, we are starting to talk about finishing tenth. We have to stay calm and have to go there to try and get three points. We have to be sure that we continue doing the things in the same way that we are doing already.
“West Ham have very difficult players – Felipe Anderson, (Marko) Arnautović, Chicharito – so they will be very dangerous. It will be a tough game and we have to concentrate and stay focussed. We can’t underestimate the opposition.
"I remember we won three games in a row and then people started to have a lot of confidence and were maybe too overconfident. West Ham were crucial in counter attacks and we suffered so we have to be sure that we don't make the same mistakes that we did in the past."
After netting his first Premier League goal against Burnley, Sean Longstaff's whirlwind year continues with the 21-year-old receiving a nomination for the Premier League's Player of the Month for February.
Since making his top-flight debut in December, the midfielder has become a key figure for Benitez's side - starting in the last ten matches - and the manager believes the midfielder is worthy of the award, who finds himself up against the likes of Manchester City's Sergio Aguero, Manchester United's Paul Pogba and Liverpool's Virgil van Dijk on the shortlist.
"We are talking about a young player coming from the system and not someone who has been in the Premier League," Benítez added. "He has had to play in the position of a senior player. He played against Liverpool and Chelsea and he was doing well.
"You have to give a lot of credit to the lad and the way he is so focused and humble, and the way he has continued working. It is fantastic news for us and, hopefully, he can get player of the month (in February).
"I think he has to win. When you compare the other players nominated with him, it is a big credit for him to be there."
