SANTA CLARA, Calif. -- Were it not for a season-ending hamstring injury to slot receiver Bruce Ellington, Jeremy Kerley almost certainly wouldn't be a member of the San Francisco 49ers.

Considering how much the Niners offense has struggled and the fact that Kerley has been, by far, its most consistent performer, that's a scary thought. To be sure, the San Francisco offense has lingered near the bottom of the league in many major categories but imagine where it would be had San Francisco general manager Trent Baalke not shipped disappointing guard Brandon Thomas to Detroit in exchange for Kerley on Aug. 29.

All Kerley has done in the time since is quickly adapt to coach Chip Kelly's offense, develop an easy rapport with quarterback Blaine Gabbert, become the team's primary slot receiver and punt returner and easily the offense's most productive option.

Never was that more evident than Thursday night's loss to Arizona when Kerley played every snap and posted eight catches for 102 yards and a touchdown. It was the first 100-yard receiving performance from a 49er this season.

“He’s a dynamic player," Kelly said. "I think the first thing when you notice Kerls is he can get in and out of cuts very quick. He’s sudden in terms of what he does. He can make people miss. He’s got real good short-area quickness and he’s got outstanding hands. I think he’s, Blaine seems to find a comfort level with him. He wasn’t 100 percent last night because he did get banged up in the Dallas game, but came back and obviously contributed. I think he had eight catches for us and did a nice job in there working it, working the inside, working against a nickel defender, working against a linebacker.”

Five games and less than two months into his tenure with the 49ers, Kerley has dwarfed the production of the rest of the team's pass-catchers. His 26 catches are twice as many as the team's second-most prolific pass-catcher (running back Carlos Hyde). His 304 receiving yards are good for more than double tight end Garrett Celek, who is second on the team in that category with 135. And when it comes to targets, Kerley's 44 are again more than doubling up the next closest player on the team, in this case Torrey Smith's 21.

If Kerley continues at his current pace, he'll finish with 83 catches for 973 receiving yards and six touchdowns, all of which would easily be career highs. The sixth-year veteran out of TCU had flashed such potential in the past but has never had more than 56 catches, 827 yards or three touchdowns in a season.

That Kerley has been able to have such success on such short notice is a testament to previous knowledge of a similar scheme as well as an advanced football IQ, according to Kelly.

“Well, there was a carryover for Jeremy because, I think I said this earlier, he played for the Jets under Chan Gailey and when Chan was the head coach at Buffalo [Niners offensive coordinator] Curtis [Modkins] was his coordinator and [wide receivers coach] Bob Bicknell was his receiver coach," Kelly said. "So, a lot of the things that we do, if it’s close to what he did when he was with the Jets, we can explain it because we know his language. So, we may have called it California and you guys called it New York. So, he understands and has got a pretty good feel of, ‘Hey, you ran this route for Chan. This route is similar, but we do this at the top of the stem.’ So, I think because of the correlation and because Bob and Curtis could speak Jeremy’s language of where he came from in a former system, I think it’s helped him transition. But, he’s also a really smart football player. He’s got a really good feel and good knowledge of how to be an inside receiver in this league.”

Little more than a week after the Niners and Lions finalized the deal to swap Kerley for Thomas, the Lions released Thomas. Kerley, meanwhile, has become, perhaps, the most irreplaceable part of San Francisco's offense. That probably doesn't qualify as lofty praise given that group's struggles but the Niners will take a bright spot where they can find one these days.

“He does a good job of getting open," Hyde said. "He does a good job of getting that YAC. He is a good player.”