The 26-year-old was also involved in a row with Shearer after the game, which has prompted the club to suspend him.
A Magpies statement said: "Joey Barton has been suspended from the club until further notice. The club will be making no further comment at this time."
Barton's dismissal against Liverpool means he misses Newcastle's final three games of the season because of an automatic Football Association ban, but his whole future at the club is now in doubt.
Joey Barton Tackle
Joey Barton TackleGordon Taylor, chief executive of the Professional Footballers Association, has been in contact with Barton's advisor and insisted the player is aware of the severity of the situation."He knows himself it was a bad challenge, it was bad judgement, but he has apologised to Alonso, to the referee and to the manager," Taylor told BBC Radio 5 Live.
"He realises what he has done and his reputation has gone before him.
"The mood in that dressing room afterwards would have been a feeling of frustration with Newcastle battling against relegation and this is the last thing they need and Joey knows that as well as Alan Shearer.
"It is a case of everybody loses with this one."
Joey Barton Tackle
Joey Barton Tackle
Joey Barton Tackle
Joey Barton Tackle
Joey Barton Tackle"I asked him to stay calm in the heat of the battle but it was a stupid tackle and he deserved to be sent off."Barton, who has played once for England, was a controversial figure at Manchester City before joining Newcastle for £5.8m in 2007.
He has since started only 26 matches for the Tyneside club.
In July last year, Barton received a four-month suspended sentence for assaulting Ousmane Dabo in a training-ground incident while both players were at City.
Barton was banned by the FA for 12 matches - six of which were suspended - and fined £25,000 after admitting a violent conduct charge in relation to the Dabo incident.
But Taylor said while he understands time is running out for Barton, he hopes the midfielder will be given another chance.
"The business is full of people who you wonder if they will ever learn and its the same with Joey," said Taylor.
"He has worked hard with Sporting Chance clinic and then this has happened and it is one more time.
"Of course people will run of patience but you just have to hope that he will get there eventually as soon his career will be over anyway."
