By Matthew Geagan, CBS Boston

BOSTON (CBS) — The Celtics are out west for a critical five-game road trip. To make matters even more difficult for the struggling C’s, they’ll be without their defensive backbone in Marcus Smart, who is out 2-3 weeks after suffering a left calf tear in Saturday night’s loss to the Lakers.

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First up for Boston on their trip: A matchup with Steph Curry and the Golden State Warriors. Without Smart hounding him on each possession, the two-time MVP may drop a 50 burger on the Celtics. It doesn’t get any easier going forward either, with matchups against Phoenix’s Devin Booker, L.A.’s Kawhi Leonard and Paul George and Utah’s Donovan Mitchell also on the docket on the West Coast swing.

Best of luck to Brad Stevens over the next few weeks, as the Celtics head coach will have to continue to juggle his roster and rotations. At least Stevens has had plenty of practice with that to start the season, with Kemba Walker’s balky knee and Jayson Tatum’s bout with COVID causing the Celtics to look like anything but their usual selves for large stretches.

At this point, it seems like Stevens could juggle just about anything. But replacing Smart in the lineup is not as easy as just plugging in any other guard, the head coach said Monday night after the team arrived in San Francisco. Smart has averaged 32 minutes per game this season, so navigating a stretch without him will be like throwing chainsaws up in the air and hoping for the best.

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“As far as rotating other guys and who gets those minutes, who has a chance to play that hasn’t been playing as much or who is going to play more who has been playing a little bit, that’ll be determined based on opponent over the next five games that we’re on this trip,” Stevens explained Monday.

There are two other factors that will make this even more difficult for Stevens. Walker remains on a minutes restriction, and that won’t be lifted anytime soon. And while the news on backup point guard Payton Pritchard’s injured knee was much better than anyone anticipated, the rookie won’t suit up this week. So Stevens will have to rely on a limited Walker, veteran Jeff Teague, Carsen Edwards, Tremont Waters and rookie Aaron Nesmith as his only guards for the foreseeable future. After Walker, only Teague and Waters have experience running the show at point guard.

The other sharp object thrown into the mix: The Celtics play Wednesday night, visiting the Sacramento Kings for the second leg of a back-to-back. Walker sat out last Monday night in Chicago after playing the night before, and will likely sit out Wednesday night as the team keeps him in bubble wrap. The veteran has averaged just under 25 minutes in his six games back, with his heaviest workload at 28:35 against Philadelphia on Jan. 22.

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Stevens is going to have to put on quite the show over the next few weeks, as he tries to maneuver a guard rotation that has taken two big hits over the last two weeks.