CHICAGO — Bears head coach Ben Johnson said it was possible to remake an interior offensive line in one offseason. He was right.

In fact, he and general manager Ryan Poles did it in the span of seven days. The tall task was complete on Monday, when they agreed on terms of a three-year deal with free-agent center Drew Dalman. The news was confirmed by a league source, who spoke to Marquee Sports Network on the condition of anonymity.

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NFL Network’s Ian Rapoport, who was first to report the news, stated that the contract is worth $42 million, with $28 million guaranteed. Dalman can’t formally sign the contract until Wednesday at the earliest, when free agency formally begins. The deal was worked out on Monday (and likely before) when the NFL’s negotiating window officially opened.

This news comes just a few days after the Bears completed trades for guards Joe Thuney and Jonah Jackson.

The team’s interior line was an area of grave concern entering the offseason, but it has been completely remade in short shrift.

Now it’s a team strength.

Thuney’s an All-Pro. Jackson had a track record of success working with Johnson in Detroit. Dalman was the best center set to hit the open market after four solid seasons with the Atlanta Falcons. He built a reputation as a smart player who is good with the mental side of the game. He’s a quality run blocker who has had some issues in pass protection, but it’s a tough guy and a solid locker room leader. He had the luxury of playing alongside Chris Lindstrom in Atlanta, but he’ll have quality help in Chicago with Jackson and Thuney on his flanks.

As a note, the Stanford alum is the son of Chris Dalman, who played seven NFL seasons with the 49ers, mostly as a center.

The Bears have made a major financial investment in their offensive line, which now seems set in terms of the starting lineup. They have some quality depth behind it, with room for a swing tackle in free agency or the draft.

Johnson made good on their statements of fixing the offensive front. A quality offensive line was key to Johnson’s success in Detroit, and he’s got the talent in Chicago to have success and provide time and support for quarterback Caleb Williams, who was sacked 68 times last season. Dalman’s working relationship with Williams will be key, as the duo’s charged with identifying defensive blitzes and setting up proper protections.

The Bears still have significant needs, most notably at edge rusher, defensive tackle, tight end and receiver. It will be interesting to see how they proceed through free agency and how they use a significant amount of salary-cap space.