The 25-year-old has scored 28 goals during a scintillating season that some feared could be disrupted by a lengthy lay-off after pulling up holding his groin against Everton 11 days ago.
United allayed concerns by announcing Rashford was only expected to miss a “few games”, although Ten Hag last week admitted he was unsure how much time the forward would miss.
The England international sat out the chaotic 2-2 first-leg draw with Sevilla and Sunday’s 2-0 Premier League win against Nottingham Forest, but he has made a rapid return to the fold.
Rashford trained with his team-mates at Carrington on Wednesday morning and was part of the 21-man group that made the trip to Spain for the quarter-final second leg.
Luke Shaw, Tyrell Malacia and Marcel Sabitzer also made the squad after injury, with Ten Hag saying of the quartet: “They are available because that is why they are on the airplane.
“But I will take my decisions tomorrow. Today we had training, we will see what the reaction is and then tomorrow we will take the decision.”
Pushed on Rashford, the United boss said: “All the players, you want to keep all the players fit, so that is always an objective besides of course the main objective to win the game.
“He had one session with the team, but he had some sessions before individually.”
The quartet’s return to the squad is a welcome boost to a side that travel to Spain without a number of key players.
Fernandes banned for Sevilla return
Bruno Fernandes is suspended after picking up a booking in last week’s first leg, which saw first-choice centre-back Raphael Varane and Lisandro Martinez pick up injuries.
Sevilla capitalised on that disruption and recovered from a shocking start to snatch a last-gasp draw thanks to late own goals from Malacia and Harry Maguire.
The abolition of away goals softens the blow but now United must raise their performance against six-time Europa League winners Sevilla at the hostile Estadio Ramon Sanchez-Pizjuan.
“It’s a tie about two legs,” Ten Hag said. “I think we play for over 60 minutes quite well and then the last 30 minutes we dropped the level and we became passive.
“It’s not acceptable, we know that, and you see what happened when you are playing a game for only 60 minutes.
“You can’t do it and when you do it you get punished, so we have to be aware of it.
“We have to use emotion as a tool but you have to control it as well.
“You have to put it in the right moment, so the timing for that is important and that is in big games especially, you have to know when you use it and when definitely not.”