The Giants likely must play the final five games of this nightmare season without their best player. Defensive tackle Dexter Lawrence dislocated his elbow during the team’s 27-20 loss to the Cowboys on Thanksgiving in Dallas. “I anticipate it being long term injury, the rest of the season,” head coach Daboll said Friday. “Still going to have to take a look at a few different things, but not very optimistic about it.” The Giants had only two defensive linemen — Jordon Riley and Elijah Chatman — by the third quarter of Thursday’s game because Rakeem Nunez-Roches left with a stinger and D.J. Davidson reinjured his shoulder. Daboll said Nunez-Roches was sore Friday morning and needed treatment, but it was too early to tell on the timetable of his recovery. Davidson is also sore and is day-to-day. Lawrence was well on his way to a third straight All-Pro selection with nine sacks while also being a premier run defender whom offenses frequently need to double-team. The 6-foot-4, 340-pounder was a leading candidate for NFL Defensive Player of the Year a few weeks ago. Without Lawrence — let alone the other two injured linemen — the Giants’ defense will likely go from bad to worse. The unit has allowed a league-high 5.1 yards per carry, giving up that exact average to the Cowboys’ Rico Dowdle as he rushed for 112 yards — his first 100-yard game of the season. In the passing game, the Giants led the NFL with 36 sacks through Week 10, but they’ve had none in their past two games following a bye week. They have also set an NFL record by going 11 straight games without recording an interception. Daboll said there is “definitely a chance” that the Giants sign a couple of defensive linemen given all the injuries. Undecided at Quarterback Daboll said the staff would decide later in the day Friday on who will start at quarterback when the Giants host the New Orleans Saints next Sunday. Tommy DeVito missed the Thanksgiving game because of forearm soreness. Drew Lock completed 21-of-32 passes for 178 yards with an interception and one lost fumble, but he also rushed four times for a career-high 57 yards and a touchdown and gave the Giants their first lead in a game since Week 5. DeVito, if healthy, would appear to be more likely to start largely because he didn’t turn the ball over against the Tampa Bay Buccaneers in Week 12. “We’ll evaluate the two games that both of those guys played,” Daboll said. “I thought Drew did some good things yesterday. We got to, obviously, clean up the turnovers. Turnovers, the ones that were seven points to the defense, and then back up when we get some points. We got to make sure we’re taking care of the ball. Give our guys a chance down the field to make some plays.” Johnson Done for the Year? Rookie tight end Theo Johnson has the “potential” to be out for the season as well after injuring his foot against the Cowboys, according to Daboll. Johnson, a fourth-round pick from Penn State, was the Giants’ second-leading receiver on Thursday with a career-high 54 yards. He has 29 catches for 331 yards and a touchdown this season. It’s a big loss considering Johnson has played 84 percent of the offense’s snaps. Chris Manhertz (28 percent) and Daniel Bellinger (17 percent) have been used more so as blocking specialists and have combined for only four receptions this year. The Giants also used a waiver claim Tuesday on third-year tight end Greg Dulcich, who had 464 yards on 41 catches in 16 career games with the Denver Broncos. He was inactive in the Giants’ game against the Cowboys.