While the 49ers await the ultimate decision made by center Alex Mack regarding his playing future, they have some added financial flexibility. The veteran agreed to a re-working of his contract, as detailed by ESPN’s Field Yates (on Twitter). 
Mack’s base salary will drop from $5MM to $1.12MM this season, creating some immediate cap space for San Francisco. In 2023 — the final year of his contract — his salary will decrease from $3.35MM to just under $1.2MM. Perhaps the most telling aspect of this move, however is the matter of the guaranteed money in the deal.
NFL Network’s Mike Garafolo tweets that $500K (the only guaranteed compensation Mack was due this year or next) has been converted to a roster bonus. That is significant, as it means the 36-year-old will receive the money this month, something which wouldn’t have happened if he had retired and it had remained a part of his base salary. Garafolo posits that the move represents a “parting gift” from the 49ers.
That makes today’s news another sign that Mack has played his final game in the NFL. When it was first reported that he was considering hanging up his cleats – despite having only played one season in the Bay Area on a three-year pact, suiting up for all 17 games and being named a Pro Bowler for the seventh time — team personnel made it clear their expectation was that he would return. Head coach Kyle Shanahan recently struck a much different tone on the subject, however.
“I’ve talked to him here and there,” Shanahan said last week. “I’ve been in touch with him throughout the offseason… I’ve got a pretty good idea of what he’s doing… I’m going to leave that up to Alex, but I’ve got a pretty good idea.”
If Mack does indeed retire, the 49ers would be forced to add a veteran at the center position for the second straight season. Some of the remaining options include J.C. Tretter, Trey Hopkins and Billy Price. The team now has more money to work with should it become necessary to sign one of them, but his retirement would leave another significant hole needing to be filled on the interior of their offensive line.