The third law of the NFL draft is quite simple: For every action that occurred during the three days in Nashville last week, there is an equal and opposite reaction.
The 49ers turned their six scheduled draft picks into eight selections. That does not necessarily mean all eight players added will win a job over a player who has been around for a while. But, certainly, that will be the case with some of those spots.
Here’s a look at some of the veterans who have challenges to hold on to their previous roles or, in some cases, roster spots because of the additions the 49ers made during the NFL draft:
Stay in the game with the latest updates on your beloved Bay Area and California sports teams! Sign up here for our All Access Daily newsletter.
TE Garrett Celek
Garrett Celek is not going to just let somebody take his job.
Those were the words of a 49ers source before the draft, anticipating the selection of a tight end at some point. As it turned out, the 49ers selected two players who can potentially step into tight end roles.
The 49ers selected 6-foot-5 Baylor wide receiver Jalen Hurd in the third round. Coach Kyle Shanahan mentioned that Hurd has the versatility to see time at tight end end. Then, the 49ers drafted Stanford tight end Kaden Smith in the sixth round.
San Francisco 49ers
Find the latest San Francisco 49ers news, highlights, analysis and more with NBC Sports Bay Area and California.
Celek is a seven-year veteran who turns 31 in a month. He experienced a major drop-off last season with just five catches for 90 yards while appearing in 15 games.
DLs Arik Armstead/Solomon Thomas
Arik Armstead and Solomon Thomas play defensive end on base downs before moving inside to rush the passer on nickel downs. The 49ers’ selection of Nick Bosa with the No. 2 overall pick complicates things for both Armstead and Thomas, especially if Dee Ford ends up as an every-down player at the other defensive end spot.
Then, when the 49ers go into their nickel package, you know DeForest Buckner will be occupying one of those interior spots. That means, Armstead and Thomas will compete against each other and, likely, split the pass-rush snaps.
Armstead enters his contract year. The 49ers are paying him $9 million on the fifth-year option before he is scheduled for unrestricted free agency a year from now. Thomas enters Year 3 of his original four-year contract as the No. 3 overall pick in the 2017 draft.
Because the 49ers figure to use a rotation of defensive linemen to keep everyone fresh, nobody will get aced out altogether. But somebody is going to get a lot fewer snaps through the course of the season that what is expected from a recent first-round draft pick.
WRs Marquise Goodwin/Kendrick Bourne
Goodwin started the first 24 games in which he appeared since signing with the 49ers on the first day of free agency in 2017. But Shanahan has made it clear he believes Goodwin is better-suited – and the 49ers are a better team – when Goodwin is used as a role player.
The 49ers would like to use Goodwin as Shanahan deployed Taylor Gabriel during their time together in Atlanta.
Bourne finished last season as the team’s best-producing wide receiver. As a second-year player, Bourne started eight of the 49ers’ final nine games and had a good season. He caught 42 passes for 487 yards and four touchdowns.
The 49ers clearly entered the draft with an urgent need to add to their group of wide receivers. They grabbed South Carolina wide receiver Deebo Samuel with the No. 36 overall pick. Samuel is likely to be paired on the outside with Dante Pettis, the team’s second-round pick last year.
Hurd is not likely to be one of the team’s primary targets as a rookie, but Shanahan is eager to devise some packages to take advantage of his unique skillsets. Goodwin, Bourne and veteran pickup Jordan Matthews will have to fight for their roles in the offense.
DE Ronald Blair
Blair and Cassius Marsh were the 49ers’ primary edge rushers in their nickel defense last season. They tied for second on the team with 5.5 sacks. Shortly after the 49ers acquired Ford, the club released Marsh.
[RELATED: How Lynch, Shanahan arrived at 49ers' eight draft picks]
Now, Blair has been pushed back one spot on the depth chart as the No. 3 edge rusher behind Ford and Bosa.
Blair is entering the final year of his original rookie contract after coming to the team as a fifth-round draft pick in 2016.