The Blues were dealt a blow in the warm up at Old Trafford after Alonso was forced to withdraw from the starting line-up due to illness.
Manchester United eased to three points courtesy of goals from Marcus Rashford and Ander Herrera against the Premier League leaders.
Alonso has been ever-present in the Chelsea side since Antonio Conte switched to 4-3-3 formation back in September.
The 26-year-old has scored five goals and has made two assists in 26 appearances in the Premier League in the 2016-17 season.
The former Fiorentina defender will be hoping to return to the Chelsea side for their clash against Tottenham Hotspur at Wembley on Saturday evening.
Speaking to the Daily Mail about his Premier League team of the year, former Arsenal defender Keown named Alonso as the league’s best left-back ahead of Danny Rose.
“I would stick with Kyle Walker as the right wing back but Marcos Alonso can count himself unlucky to have missed out on the left,” Keown said.
“We saw just how much Chelsea missed him against Manchester United.
“He has hardly missed a game this season and for team of the year you have to consider players who have been regularly available for selection.
“Alonso would make my team ahead of Danny Rose but would be the only Chelsea player in the back five.”
Chelsea are four points clear of Tottenham Hotspur in the Premier League table with six games to go in the title race.
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