If you abandon a match that isn't safe to leave, you can't rejoin it, your team plays a player down and you get a matchmaking penalty. Abandoning matches can also put you in the Low Priority queue, which you only get out of by winning games.
Leaving vs disconnecting
If your game crashes or your connection drops, the match carries on and Deadlock offers to put you back in: "Match in Progress. Would you like to reconnect?" Choose Reconnect to get back into your game.
Abandoning is different. Pressing Abandon in a match that isn't safe to leave shows a warning first: "You will not be able to reconnect to this game, your team will be down a player and a matchmaking penalty will be applied." Confirm and the penalty is yours.
When it's safe to leave
If a teammate abandons, the game can tell the rest of the team "It is now safe to leave".
- Leaver gone in the first 5 minutes: the match isn't scored, and everyone except the leaver and their duo can leave without a penalty.
- Leaver gone after 5 minutes: the match isn't scored for the leaver's team, and they can leave without a penalty.
- In ranked, the message reads "You can no longer lose ranked points this match; it is now safe to leave."
Either way, if you stay and win, it still counts as a win.
Low priority
"Players who intentionally grief or abandon matches will be put into a separate Low Priority Matchmaking queue", where you're only matched with other low priority players. Reports from other players for bad behaviour can put you there too.
- How to get out: win the number of games the play menu shows. Waiting doesn't clear it.
- In a party, the whole party queues in low priority. Win the games together, or play without the penalised player.
- While you're in it, you can't queue for ranked, Street Brawl or Hero Labs.
A separate matchmaking ban also exists, and it stops you playing ranked while it lasts. For the rest of the ranked rules, see how to unlock ranked.
Quick answers
What happens if you leave a match in Deadlock?
You can't rejoin it, your team plays a player down and you get a matchmaking penalty. Doing it often puts you in the Low Priority queue.
Is there a penalty for leaving in Deadlock?
Yes, unless the game says it's safe to leave. That happens when a teammate abandons first.
How do you get out of low priority in Deadlock?
Win the number of games shown in the play menu, in the Low Priority queue. Only wins clear it, not time.
Can you reconnect to a match in Deadlock?
Yes. If you disconnect or crash, the game offers to reconnect you to the match in progress. Only abandoning locks you out.