Jürgen Klopp has acknowledged that Liverpool were "too optimistic" over the return of Philippe Coutinho, who is set to miss out on their trip to Newcastle United this Sunday.

The Brazilian had scored four goals in three games before picking up a hamstring injury which forced him off midway through the second-half of the Reds' 4-1 crushing of Manchester City last month.

The 23-year-old's knock has kept him out of their last three games, wins over Bordeaux, Swansea City and Southampton, though there was confidence that Coutinho would soon be back in the first-team - having been in contention for the journey to the south coast for their Capital One Cup quarter-final with the Saints.

But despite returning to training, Coutinho has complained of not feeling fully fit - which is likely to mean he misses their fixture against 18th-placed Newcastle.

Coutinho unlikely to feature against Magpies

Klopp, when asked for an update on the forward's fitness, insisted that whilst he likes optimism - the reds were "too optimistic" and acknowledged it as something that "sometimes happens like this."

He was insistent that there was no-one to blame or criticise over the situation, saying Coutinho "tried everything he could" and trained "nearly normally" but simply "doesn't feel comfortable."

The German added that they must "take care" of the No.10's knock, labelling the muscle "a dangerous thing" and stating "when you don't feel comfortable, then stop."

Klopp explained that Liverpool "will wait" and he will play "no problem" if somebody says he's "available" - stating that "nobody" gave him "the sign" for him to be involved against Newcastle - so they will have to "wait again."

Klopp glad to have Sturridge and Henderson back

Though Coutinho will miss out on the trip to St James' Park, Daniel Sturridge is likely to be involved after Klopp revealed the striker came out of the mid-week win at Saints, where he netted a brace, feeling healthy.

Klopp said that the striker "did well" and explained that it was always "the plan before the game" for him to only play an hour of football before being withdrawn, calling it "completely normal" for a player like Sturridge "with a long injury history."

He joked that the England international "felt each muscle" afterwards but dismissed it as nothing serious, insisting it's "normal" after an "intensive" game. 

The Reds boss vowed that, currently, Sturridge is "available for the weekend" and he and his backroom staff "will have to see" whether they decide to start him.

Jordan Henderson further boosted the number of options available to Klopp, coming on as a second-half substitute for the second successive game as he continues his recovery from a foot injury.

Klopp said that Henderson is a "good example" of how and why players "have to be handled differently" - labelling the industrious captain as a "worker" who needs to be "absolutely fit." 

He added that it is "better" for Henderson to feature off of the bench at the minute, calling it "perfect" to have him as an option after making a "big step" inside the last few weeks.

But he did admit there were concerns over his heel injury, which has proved troublesome since April, saying there were "some doubts" over the problem - but saying he "feels good" which is "really good" and "important" for Liverpool given their fixture list in December and January.

Boss pleased with increased squad depth 

And with Henderson and Sturridge back in the squad, Klopp believes competition for places is back at the level it should be - after the strength in depth they had off the bench on Wednesday evening.

Referring to the options on the sidelines, Klopp said "that's how it should be" and hoped that it stays like that to have "more than you need."

He said they "had to change" because it would have "not been possible" to play with the same team that beat Swansea, adding he doesn't know "how many" changes he will make for Newcastle but acknowledged that they have "some options."

The manager insisted they could potentially "play with the same team" because of the longer break - saying "Wednesday to Sunday is enough of a recovery" so they could "do the same again."