The Cowboys took their own sweet time in free agency, but now it looks like they are systematically plugging one hole after another. Ian Rapoport of NFL Network reported very early this morning that the Cowboys are expected to sign OG Marcus Martin.

Free agent interior O-lineman Marcus Martin is expected to sign with the #Cowboys, source said. Most recently from the #Browns, the former #49ers third-round pick visited Dallas last week. — Ian Rapoport (@RapSheet) March 25, 2018

Free agency officially opened on March 14, but the Cowboys waited for almost a week before getting in on the action, much to the chagrin of many a Cowboys fan. But the Cowboys front office has been busy the last few days:

If the report about Martin is true, that would make him the fifth free agent signing in six days. The 24-year-old Martin can play all interior spots, and would be a good fit as a backup.

Here’s a mini-report on Martin:

The 2014 third-round pick out of USC spent the first three-seasons of his career with the 49ers, including a 2015 campaign where he started 14 games. However, the lineman only played in four games (two starts) in 2016 before landing on the injured reserve. After being waived by San Francisco last offseason, he was claimed by the Browns. He ultimately didn’t take the field for a single game for Cleveland. Considering Martin’s ability to play both offensive guard and center, he’d be an easy fit as a reserve for any team.

The Cowboys are trying to build some depth along the offensive line, and more moves are expected to come in the draft. In his QB Catalog, Cian Fahey explains why:

[Dak Prescott's] supporting cast lost multiple offensive linemen (Ronald Leary and Doug Free) which forced La'el Collins to move from left guard to right tackle, creating multiple weak spots on a line that previously had none. That was when the unit was fully healthy. When Tyron Smith was hurt, Prescott was being sucked into a black hole on his left side.

Cowboys free-agent offensive linemen linemen have done well in the recent past, with Jermey Parnell signing a five-year, $32.0 million contract with the Jaguars in 2015, and Jonathan Cooper signing a one-year, $5.0 million contract with the 49ers this year. Perhaps that's part of the reason the Cowboys were able to sign both Cameron Fleming and Marcus Martin this year.