U.S. men's national team star Christian Pulisic will continue on the sidelines after suffering an injury setback, according to Chelsea manager Frank Lampard.

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Pulisic, 21, has not played since Dec. 26 due to a lingering leg muscle injury, with Lampard saying the club will reassess the player's status after the Premier League's staggered midseason break.

"We tried to get him out there last week, step it up a little bit, but we had to pull out of that," Lampard said. "The break might have come at a good time, it buys us a couple of weeks."

Chelsea's next fixture will be against Manchester United on Feb. 17. They remain in fourth place in the Premier League standings, but have not won in three straight matches.

Lampard said not being able to have a player like Pulisic has hampered Chelsea's attack. Prior to his injury, Pulisc had overcome a slow start to net six goals and six assists in 23 appearances across all competitions.

Pulisic made the move to Chelsea from Borussia Dortmund last year in a $73 million move, the highest ever paid for an American player.

"Of course you miss him. He's a quality player and he was having a really good patch pre-Christmas. Others have to stand up too, but of course we'll be happy when he's back," Lampard added.

Pulisic last featured for the U.S. in their 2-0 loss to Canada on Oct. 16 in CONCACAF Nations League action.