Bryant was denied the chance to go up against his former team when he returned a positive result just ahead of Baltimore's clash with the Dallas Cowboys.
The Ravens, who have been hit by a raft of coronavirus cases over recent weeks, managed a 34-17 triumph in the three-time Pro Bowler's absence, with quarterback Lamar Jackson – returning from his own quarantine period – claiming Baltimore were desperate to win for Bryant.
Baltimore became only the third team since at least 1940 to record at least 100 rushing yards – they had 161 by halftime – in 35 successive games, but they will now be without another key player.
Bryant will be sidelined for at least 10 days, meaning he will miss Monday's game against the Cleveland Browns.
The 32-year-old, who initially suggested he was not going to play again this season but has since changed his mind, also claimed he tested negative, tweeting on Thursday: "I tested negative back to back for COVID and I'm not excited about it."
The Cowboys tied their quarterback to a four-year deal reportedly worth $160million on Monday, a day before Tuesday's deadline to place the franchise tag on impending free agents. Dallas tagged Prescott last offseason.
Reports say the agreement, which brings to an end one of the longest-running QB sagas in the league, will see Prescott receive $126m guaranteed in a deal that contains a no-trade clause.
Tad Prescott, Dak's brother, was among the first to react and he wrote on Twitter: "Let's go, Dak. Time to win the Cowboys a Super Bowl."
Former Cowboy Dez Bryant suggested the positive resolution was absolutely vital to the team's title hopes.
He compared the stand-off to running back DeMarco Murray's Dallas departure in 2015, shortly after a controversial playoff loss to the Green Bay Packers.
"The Dak situation started to remind me [of when] we let DeMarco walk in '15," Bryant posted.
"Me, personally, I knew our chances of having a chance to win the Super Bowl [were] gone.
"It wasn't the catch [against Green Bay], it was DeMarco leaving the team which made me feel hopeless. Smart decision, Cowboys."
DeMarcus Ware, Bryant's former team-mate, added: "Congrats, Dak. Go finish what you started."
The Cowboys were 6-10 in 2020 and have not played an NFC Championship Game since winning the Super Bowl at the end of the 1995 season.
Prescott has work to do to make the team competitive again, having missed much of last year following a devastating compound fracture of his right ankle in the Week 5 win over the New York Giants.
He has the backing of several big names, however.
Los Angeles Rams cornerback Jalen Ramsey wrote: "It's always earned. Nobody just giving out free money lol. Congrats, Dak."
Free agent wide receiver Golden Tate said: "Congrats to Dak and the best agent in the biz Todd France!"
And NBA All-Star Donovan Mitchell added: "Get paid, my guy! Dak, congrats!"
Ex-NFL defender Darius Butler even suggested Prescott had got a better deal than Patrick Mahomes, the Kansas City Chiefs QB who signed the most lucrative contract in sports.
He wrote: "I'm not a contract specialist but I feel like Dak got a much better deal than Mahomes.
"$75M in year one. $66M guaranteed at signing. No trade, no tag. Back at the table at age 31 at the latest."
Bryant was set to reunite with former team the Cowboys on Tuesday, but the three-time NFL Pro Bowler surprisingly announced he had contracted COVID-19 moments before the game started in Baltimore.
Bryant tweeted: "Tell me why they pull me from warming up so I can go get tested... my s*** come back positive... I tested positive for Covid WTF.
"The crazy thing is I have the same damn routine.... this s*** do not make sense to me."
The Ravens – welcoming back star quarterback Lamar Jackson following 10 days in self-isolation – then confirmed Bryant had been scratched due to an "illness".
Bryant, who spent eight seasons in Dallas before being released at the end of 2017, later added: "Yea I'm going to go ahead and call it a quit for the rest of the season... I can't deal with this.
"Since I tested positive for Covid before the game do the game stop or go on? @NFL."
The Ravens-Cowboys contest was originally scheduled for last Thursday, but it had to be pushed back due to a coronavirus outbreak within the Baltimore franchise.
The outbreak forced the Ravens-Pittsburgh Steelers meeting to be rescheduled multiple times before taking place last Wednesday.
Bryant had not played a snap since the 2017 season after suffering a torn Achilles tendon in practice just two days on from signing with the New Orleans Saints in 2018.
But Bryant has made three appearances for the Ravens since joining the team's practice squad in October.
Bryant has not played a snap since the 2017 season after suffering a torn Achilles tendon in practice just two days on from signing with the New Orleans Saints in 2018.
The 31-year-old wide receiver, who led the NFL in receiving touchdowns in 2014, came close to joining the Ravens previously.
"My emotions running high right now… I'm thankful… I can't stop crying," Bryant wrote via Twitter.
"Put a shield over what you love and never give up… #flocknation #charmcity."
Bryant spent eight seasons with the Dallas Cowboys before leaving at the end of the 2017.
His best seasons came in Dallas, where the veteran had 531 receptions, 7,459 yards and 73 touchdowns.
From 2012 to 2014, Bryant had at least 88 catches, 1,200 receiving yards and 12 touchdowns, while earning Pro-Bowl selection in 2013, 2014 and 2016.
The Baltimore Ravens (5-1) face AFC North leaders the Pittsburgh Steelers (6-0) in a top-of-the-table clash on Sunday.
Jackson took the league by storm during his MVP campaign in 2019 as the Ravens posted a 14-2 record before losing to the Tennessee Titans in the Divisional Playoffs.
The Ravens QB, however, has found the going tougher during the early stages of this season.
Jackson ranks 27th in passing yards (1,343) – well adrift of leader Matt Ryan (2,462) – and 30th in completion rate (60.5 per cent).
The 23-year-old has completed 115 of 190 passes for 1,343 yards, 12 touchdowns and four interceptions through seven games.
As the Ravens (5-2) prepare to face the Indianapolis Colts on Sunday, Harbaugh told reporters on Friday: "He still has a lot to learn, but the great thing about Lamar is he recognises that.
"He understands that people are making him the focus. He has got to find a way to tighten up his game and beat those things with precision and accuracy and his mind.
"They're doing everything they can with a lot of smart and talented people to stop Lamar Jackson the week that they play him."
Harbaugh was also asked about three-time NFL Pro Bowler Dez Bryant, who joined Baltimore's practice squad last month, having not played a snap since the 2017 season.
Bryant suffered a torn Achilles tendon in practice just two days on from signing with the New Orleans Saints in 2018.
The 31-year-old wide receiver, who led the NFL in receiving touchdowns in 2014, came close to joining the Ravens previously.
Bryant spent eight seasons with the Dallas Cowboys before leaving at the end of the 2017.
He will not be involved against the Colts, with Harbaugh saying: "When we feel like he's ready to come up in shape and knows the offense well enough and has enough capability with Lamar on enough plays, then we'll bring him up.
"When it happens, I think it'll happen. I don't think it's something you want to force feed in there. So, we'll just have to see as we go."
Bryant's best seasons came in Dallas, where the veteran had 531 receptions, 7,459 yards and 73 touchdowns.
From 2012 to 2014, Bryant had at least 88 catches, 1,200 receiving yards and 12 touchdowns, while earning Pro-Bowl selection in 2013, 2014 and 2016.
Bryant, a three-time Pro Bowler who led the NFL in receiving touchdowns in 2014, has not played a snap since the 2017 season.
He signed with the New Orleans Saints in November 2018 but suffered a torn Achilles in practice after just two days with the team.
The 31-year-old said this month on Twitter that he just wants "a chance" and it appears league MVP Jackson would have no issue with the Ravens handing him that opportunity.
"We've got a lot of great receivers on the team right now," Jackson said on Tuesday.
"It's up to the front office. I've been seeing Dez Bryant on Instagram and stuff like that, running his routes, competing against cornerbacks.
"He's looking pretty good on social media. If the front office likes him, we'll have to see when he gets here."
The Ravens are inexperienced at the receiver position. They drafted Marquise Brown in the first round and Miles Boykin in the third round of last year's draft and added the third-round selection of Devin Duvernay and the sixth-round pick of James Proche in 2020.
Jackson has been impressed with the effort that group is showing to this point in training camp.
"They're workaholics right now," Jackson added. "It's just the second day. We're just going to have to keep stacking."
Baltimore beat the Cowboys 34-17 in Week 13.
They did so despite being one player short on their matchday roster after wide receiver Bryant was ruled out close to kick-off, much to his frustration ahead of facing his former team.
He received an inconclusive COVID-19 test result but subsequently had a rapid-result positive.
It meant the Ravens had to remove him from the roster even though their inactive players had already been announced.
Going forward, NFL.com has reported a team can elevate or activate a new player up to 30 minutes before kick-off, even if they have previously been declared inactive.
Prior to the change, the rule was players could only be activated up to 90 minutes before the start of a game.
After the Cowboys win, a Monday Night Football thriller between Baltimore and AFC North rivals the Cleveland Browns saw the Ravens triumph 47-42, improving to 8-5 for the season.
Bryant was activated from the team's reserve/COVID-19 list on Tuesday.
Bryant missed back-to-back games against the Dallas Cowboys and Cleveland Browns after returning a positive coronavirus test on December 8 – just prior to kick-off ahead of his reunion with former team the Cowboys.
The three-time Pro Bowler is now free to re-join the Ravens in practice as Baltimore prepare to face the Jacksonville Jaguars on Sunday.
Bryant had not played a snap since the 2017 season after suffering a torn Achilles tendon in practice just two days on from signing with the New Orleans Saints in 2018.
But Bryant has made three appearances for the Ravens since joining the team's practice squad in October.
Bryant was re-tested after returning an inconclusive result, and when the subsequent test was positive, he was pulled from the game, which finished in a 34-17 success for the Ravens at M&T Bank Stadium.
It was set to be the three-time Pro Bowler's first chance to go up against the Cowboys since he was cut after eight years with the team in April 2018.
Jackson, back in the side after missing the 19-14 loss to the Pittsburgh Steelers in Week 12 following a positive COVID-19 test of his own, only threw for 107 yards on 12-of-17 passing with two touchdowns and an interception against Dallas.
The reigning MVP also had a 37-yard rushing TD in the first quarter, making him the first player in NFL history with at least 5,000 passing yards and 2,500 rushing yards in his first three seasons.
Jackson also became the second quarterback in the Super Bowl era to have a rushing touchdown and a passing touchdown of at least 30 yards in the first half of the same game, after Tim Tebow in December 2010.
Asked about Bryant's withdrawal, Jackson said: "We were looking around for him, then he told us.
"It was like, we're just going to have to pull the game for him; we've got to win that game for him, because we know how much it meant to him.
"He's been talking about it for a minute now since he's been here. So, I don't like what happened, but it is what it is. We got the victory for him. I'm feeling for him, though, because I know this is a game he wanted to be in."
Jackson revealed he was still experiencing some of the symptoms associated with COVID-19 but felt good being back on the field.
"I had little flu-like symptoms. I still can't really taste or smell but I'm good now. That's a fact that calms me," said Jackson.
"I guess my sense of taste and smell is going to come back sooner or later, but I'm good now. I wouldn't wish that on anybody, though. It's not good to have."
Bryant's positive test left the Ravens' passing game short a man, but they continued to impress on the ground.
Baltimore became only the third team since at least 1940 to record at least 100 rushing yards – they had 161 by halftime – in 35 successive games.
