Fooch's Note: Mike Garafolo provided some details. Goodwin's salary was decreased from $3.7M to $2.5M. $1 million of the deal was guaranteed in exchange for the lowering of the base salary. That's $1.2 million in cap space.
We do not have the numbers yet, but it likely involves a pay cut in his base pay. Heading into this season, Goodwin was scheduled to earn $3.7 million in base salary, and would have a cap hit of $5,016,668. Given that this is the last year of his deal, there is nothing to be gained from turning base salary into signing bonus money (which could be pro-rated over a multi-year deal). So, unless the team extended Goodwin (which is pretty unlikely), he has taken a straight pay-cut.
The move sheds some light on a couple things. First off, the team has three draft picks left to sign and did not have enough cap space to make the deal happen. Prior to yesterday's announcements of Tank Carradine and Vance McDonald signing their rookie deals, the NFLPA Top 51 cap report listed the 49ers with $1,303,262 in cap space. That would not be enough space to finish up their rookie deals.
The second issue is Goodwin's roster spot. The 49ers have had Daniel Kilgore working with the number ones during OTAs because Goodwin is back home working out. Joe Looney has also gotten some work at center over the last year, so the team is obviously considering the future at center. In taking a pay cut, I have to think Goodwin's roster spot becomes a little more secure for this year.