Ryan Fitzpatrick’s first two starts this season were so poor that the Titans were more than eager to welcome Jake Locker back from injury — even if he wasn’t completely healthy.

A ninth-year pro, Fitzpatrick threw four interceptions in those games, fumbled three times and posted a 53.2 passer rating, which was hardly the kind of production the Titans expected when they signed him to a two-year, $6.5 million deal in March.

But just a few weeks later, Fitzpatrick appears to be a brand-new quarterback.

In one relief appearance against the Jaguars and one start against the Colts, he has completed 72 percent of his passes (44-of-61), thrown three touchdowns and zero interceptions, and produced a passer rating of 111.8.

His second tour of duty may not have produced a victory yet, but Fitzpatrick looks much more like what the Titans envisioned: one of the league’s top backup quarterbacks.

“I really wasn’t worried because there was so much more to it than him just throwing interceptions,” wide receiver Nate Washington said. “As receivers, we probably could have been better in our timing and we could have been in better places, so all that stuff didn’t sway me one bit. We still believed in Ryan 110 percent — it was just a matter of us all getting on the same page.”

What’s behind Fitzpatrick’s turnaround? Here are four factors:

Tweaking the system. The Titans didn’t tailor the offense to Fitzpatrick earlier because they knew Locker would be returning in a few weeks.

But they made changes last week with Fitzpatrick in mind, such as a far greater use of the no-huddle system and increased use of the no-backs set. He was used to both approaches from his days with the Bills, and the results were apparent against the Colts: He was 22-of-28, and three of the incomplete passes were drops.

“The empty backfield set Jake’s not comfortable with and Ryan is, and Ryan’s comfortable with the tempo stuff and Jake wasn’t,” offensive coordinator Dowell Loggains said. “So it gave (Fitzpatrick) an opportunity. It’s something we worked on through training camp and OTAs with both of them, and we felt like (against the Colts) it gave us a little bit of an advantage.”

Targeting a talented twosome. Fitzpatrick has made extensive use of slot receiver Kendall Wright and tight end Delanie Walker.

In his last two games, he threw 20 passes to Wright and completed 16, and he threw 17 passes to Walker and completed 14 (including two touchdowns). So overall, Fitzpatrick has 30 completions to Wright and Walker over the past two weeks, with a combined 14 completions to all the other Titans receivers.