The already-depleted San Francisco 49ers offense took another hit, as another key player is set to miss some time.

49ers head coach Kyle Shanahan told reporters on Monday that star receiver Deebo Samuel will miss "a couple weeks" due to a calf strain.

Samuel led San Francisco with eight catches and 110 receiving yards in Sunday's 23-17 loss to the Minnesota Vikings. Per ESPN's Nick Wagoner, Samuel told Shanahan that he thinks he injured his calf while making a short catch late in the game.

Losing Samuel leaves the 49ers without another one of the biggest sources of production on offense. San Francisco has already been without star running back Christian McCaffrey for the first two games of the year while he recovers from Achilles tendonitis. Shanahan said after Sunday's game that the return timeline for the reigning NFL Offensive Player of the Year remains unclear.

"Nobody knows," Shanahan said when asked about McCaffrey's potential return. "We're dealing with tendinitis so, not one person knows. He doesn't know. We don't know and [we will] take it day by day."

The 49ers placed McCaffrey on injured reserve on Saturday, so the earliest he will be able to return is in Week 6 against the Seattle Seahawks.

Without Samuel, San Francisco quarterback Brock Purdy will have to spread the ball around to multiple players for the team's offense to be effective. Star tight end George Kittle will be counted on to take pressure off the outside receivers by producing over the middle.

The reigning NFC champions will do their best to stay afloat until Samuel and McCaffrey are able to return to the lineup and try to help them make a second straight trip to the Super Bowl.