HOUSTON -- It’s a stat that has been reiterated all offseason: The Houston Texans allowed an NFL-leading 62 sacks last season.

After only signing tackle Matt Kalil in free agency, Houston general manager Brian Gaine still had work to do going into the draft. Houston added two tackles: Alabama State’s Tytus Howard in the first round (No. 23) and Northern Illinois’ Max Scharping in the second (No. 55).

While the ideal scenario is that a rookie offensive lineman would not have to contribute immediately because there is "a big adjustment" for them, according to Texans coach Bill O’Brien, it’s likely Houston will have to rely on Howard, and perhaps Scharping, right away.

Unless tackles Kalil and Seantrel Henderson blow the Texans away in training camp, Howard is expected to start at one of the tackle spots, likely on the left side. But Gaine likes the flexibility that Howard could provide because the Texans believe that Howard can be a four-hold player, meaning he could line up at either tackle or either guard spots. Houston has plenty of options at guard with Howard’s versatility. Zach Fulton and Senio Kelemete started there last season, and there’s a belief that 2018 draft pick Martinas Rankin could also be a better fit at guard in the long haul. Veteran Greg Mancz can also fill in at any of the three interior offensive-line positions.

For Howard and Scharping, O’Brien said there’s not only a big difference from “a strength standpoint [and] from a knowledge standpoint” on the offensive line compared with college football, but that most of the linemen are in two-point stances instead of three-point stances.

“They’re not run-blocking a whole lot [in college] -- some of these schools [are] throwing the ball 60, 70 times a game,” O’Brien said. “So they’re backpedaling. Now you’ve really got to train the guy how to run block because we have to be able to run the football. There’s a lot that goes into it. Then they go from blocking who they blocked in the ACC, the Big Ten, the SEC to now the first day of training camp, they’re blocking J.J. Watt, Jadeveon Clowney, Whitney Mercilus.

“So, there’s a big adjustment, but if they have a great work ethic and they stay true to who they are, they’ll develop and they’ll be able to play their first year. But, it’s not easy.”

Not only is there a jump in talent from college football to the NFL, but both linemen are coming from schools outside the Power 5 conferences -- and in Howard’s case, outside the FBS.

At rookie minicamp, O’Brien said the plan will be to have Howard and Scharping play both guard and tackle during the Texans’ OTAs this spring and during training camp, although Howard will spend a lot of time at left and right tackle.

“Both guys are very smart guys,” O’Brien said. “In the brief time that we've had them, they’ve picked up a lot of what we're trying to do. Really sharp guys, good guys, and we're thrilled to have them. I mean, absolutely thrilled to have them."

Although the linemen have impressed early, O’Brien knows there’s a lot of work to do before they can line up to protect Watson, who also needs to improve how quickly he releases the ball in the pocket.

“These guys [are] really getting used to the technique and the speed and the strength of the game, because that's a huge adjustment when you jump to this league,” O’Brien said. “Then, on the inside, it's the same thing. Strength and speed, and then making sure that they understand the information so they can learn and get out there and play."