Darnell Dockett's signing with 49ers an endorsement for Jim Tomsula

Mike Nolan, the man who brought Jim Tomsula to the NFL, said his charge could command a room. Just give him a chance.

Drew Henson, who knew Bo Schembechler and played for the likes of Joe Torre and Bill Parcells, said his coach in NFL Europe with the Rhein Fire had a similar presence and impact on his players.

Timmy Chang, who set passing records at Hawaii before hanging loose halfway around the globe in Germany with Tomsula, spoke of how “real” his pro coach was, how genuine his persona was for any and all associated with the program.

And you scratched your head after watching Tomsula’s disastrous introductory news conference as head coach of the San Francisco 49ers in January and wondered what Nolan, Henson and Chang were thinking. Plus, given the time it took the Niners to fill out a coaching staff -- one that, on first impression, was on the underwhelming side -- you had to fear the worst for quality free agents wanting to come to Santa Clara, California.

But after Darnell Dockett, a three-time Pro Bowl defensive tackle with the Arizona Cardinals, agreed to join the division rival Niners on Thursday, maybe Nolan, Henson and Chang knew exactly what they were talking about.

Just give Tomsula a chance in a one-on-one setting and let the chips fall where they may.

Indeed, Dockett’s arrival could be a sign to any and all quality free agents that this Tomsula cat ain’t the same guy they saw being lampooned. Because if Dockett wants to play for him … well, you get the picture.

Plus, it shows that the Niners, who usually sit out the early frenzy of free agency, are serious about reloading, rather than rebuilding. Consider: With five-time Pro Bowl defensive end Justin Smith still contemplating whether to retire or return for a 15th season, getting Dockett shows the 49ers are not going to sit idly by and merely hope for the best.

If Smith does come back, Dockett would ostensibly be replacing Ray McDonald as an end in the Niners’ 3-4 defense, and if everyone is healthy, imagine a front seven of Smith and Dockett at ends, Ian Williams at nose tackle and Aldon Smith and Aaron Lynch at outside linebackers with a couple of All-Pros in the middle in Patrick Willis and NaVorro Bowman. Depth on the defensive line comes in the form of Quinton Dial, Tony Jerod-Eddie, Mike Purcell, Tank Carradine and Glenn Dorsey.

Not too shabby, right?

Injuries devastated the defense last season, even if the likes of Chris Borland, Michael Wilhoite and Dan Skuta were more than capable replacements for former defensive coordinator Vic Fangio.

But adding Dockett gives new defensive coordinator Eric Mangini another toy with which to play. So long as he, like so many other 49ers, is healthy.

The 6-foot-4, 293-pound Dockett, who turns 34 on May 27, missed all of last season after tearing an ACL in training camp. But before that, he had missed only two games in his first 10 seasons, all of which were with the Cardinals after they chose him in the third round of the 2004 draft out of Florida State.

The Cardinals released him last week, saving $6.8 million in salary-cap space, after 158 games in which he had 462 tackles, 40.5 sacks and four interceptions.

Dockett has spoken highly of the notion of loyalty. So the Cardinals parting ways with him must cut deep. He will want payback twice a season. And that’s a good thing for the Niners, who not only strengthened themselves but also weakened a division rival in the process.

After being cut, Dockett tweeted the following:

Maybe that’s what the talk was about between Tomsula and Dockett. As Nolan said, just give him a chance.