Back in the Saddle

Not Exactly What It Says on the Tin: When someone who no longer fights on the front lines, perhaps because they got promoted to a desk job, or decided that they were getting too old for this and retired, returns to battle, either out of boredom or necessity. Can often apply to The Captain, a Four-Star Badass, or maybe even The President or the King.

Related to Ten-Minute Retirement. In the case of Back in the Saddle, the retirement or promotion typically won't happen in the same story arc as the return to the action. This trope also applies to being Kicked Upstairs or being otherwise made into a Desk Jockey.

A sister-trope to He's Back, where the hero is out of action because of a Heroic BSOD or otherwises loses his groove.

If a group is involved, may require Putting the Band Back Together.

Anime and Manga

 * An unusually young example, but... in Zeta Gundam, Amuro Ray - the Ace Pilot from the original Mobile Suit Gundam - is retired, and living in virtual house-arrest, since the Terran Government suspects that he might have spacer sympathies. As it turns out, they're right - after an encounter with the new hero, Kamille Bidan, he decides to join up with the AEUG, and jump back into the pilot-seat of a Humongous Mecha. (Though, sadly, he didn't retrieve the original Gundam from the nearby museum as many probably had hoped.)
 * In the final few episodes of Macross 7 both Max and Miria retake their positions as Valkyrie pilots and it is glorious.

Comic Books

 * Both The Dark Knight Returns and Kingdom Come feature superheroes coming back from retirement.
 * And in The Dark Knight Returns, Batman literally gets in a saddle.

Films -- Live-Action

 * Hot Shots! Part Deux. After Topper Harley's I Will Fight No More Forever retirement from the military, he's called back to duty when his old boss is captured while on a rescue mission.
 * Independence Day: President Whitmore, getting back in the cockpit to rally the surviving military forces after they have been on the wrong side of a Curb Stomp Battle in order to Save the World.
 * Quite a few of the other pilots were long-since retired, including Russell, who hadn't flown a military jet since the Vietnam War.
 * Predator. Dillon, who at one time been one of Dutch's comrades but ended up a pencil pusher at the CIA. He went along on the mission to save his CIA friends.
 * Space Cowboys. A team of retired test pilots are called into action to repair a faulty satellite.
 * Star Trek the Motion Picture. Captain Admiral Kirk, who's been working a desk as Chief of Naval Operations for several years, uses the V'Ger crisis to get himself returned to the Enterprise. This is a Subverted example in that Admiral Kirk is not in fact in command of the Enterprise, but rather is in command of the mission the Enterprise is on. Captain Dekker has the responsibility (and arguably, the fun) of commanding the ship itself.
 * Star Trek II the Wrath of Khan: Doctor McCoy implores Admiral Kirk to get out from behind the desk and get in another starship, "before you really do grow old."
 * Admiral Kirk initially tries to insist that Captain Spock, the ship's commander, stay in command of the ship during the mission, as Captain Dekker did in the previous film, but Spock insisted that the Enterprise rightfully belonged to Kirk. Maybe because he knew what happened to the last guy.
 * And of course, in Star Trek Generations, Kirk gives Picard a piece of cautionary advice to never let himself be put behind a desk.
 * Starship Troopers. Rico's teacher Mr. Rasczak retired from the Mobile Infantry and became a school teacher, probably because he lost part of his left arm. After the start of the Bug War he rejoins the Mobile Infantry with the rank of Lieutenant, with a cybernetic replacement on the stump of his arm. There's also Drill Sergeant Zim, who is so eager to get back on the front lines that he deliberately gets himself demoted to Private to do so.

Literature

 * In Harry Potter, Mad Eye Moody is retired but is called back to active service by Dumbledore when Voldemort comes Back From the Dead.
 * In the Deathstalker series as part of Owen's plan to overthrow Empress Lionstone they plan to recruit Jack Random, the "professional rebel". To their surprise, Random is now an old, world-weary retiree who, after one defeat too many, has taken up janitorial duties. They manage to bring him back in and he proves to still have a good bit of fight in him.

Live-Action TV

 * Buck Rogers in The 25th Century episode "Return of the Fighting 69th". A long retired bomber pilot and the rest of the crew from his squadron are called back to duty because they're the only ones who can navigate a treacherous asteroid belt.
 * Stargate SG-1 has had General Hammond coming to The Squad's rescue on a number of occasions. The most noteworthy case probably being when he showed up with his Big Damn Gunship in the Season 7 finale.
 * General O'Neill got to pull one of these in a later season when The Squad finds an Atlantean Puddlejumper, which he uses to save the day because he is one of the few people they know of who can operate one.
 * In Upstairs, Downstairs, James Bellamy is given a staff job when his views on the battle of Mons in World War One are made public by Tory sympathisers. Later on, due to the frustrations of being away from the real fighting, and with the help of Hazel, who pulls a few strings for him, he returns to the front as a Major.

Videogames

 * In Ace Combat Zero, Dietrich Kellerman, the legendary Belkan Ace Pilot-turned-Veteran Instructor (and you have to be really good to become a legend of the Belkan Air Force), is sent back to the frontlines during the Belkan War to boost the troops' morale.
 * In Metal Gear Solid, Solid Snake gets back to business is kidnapped and forcibly recruited after retiring to raise sled dogs in Alaska.
 * From Metal Wolf Chaos we have MICHEAL Wilson, PRESIDENT OF THE UNITED STATES, who fights for BURNING AMERICAN JUSTICE after being betrayed by his Vice President RICHAAAAAAARD Hawk.
 * This gets Lt. General Raul of Radiant Historia killed in one of many false bad endings.

Western Animation

 * In Batman Beyond, Bruce Wayne has long-since retired from being Batman due to old age and a crippling heart condition. He now mentors and acts as the Voice with an Internet Connection to the new Batman. However, on two occasions he's taken up the fight again. On the first, he did it with the aid of Powered Armor. On the second, he was returned to a younger age through the use of a Lazarus Pit. Both times, his heroic theme from Batman the Animated Series plays for him. Both can be conveniently watched here.
 * In The Powerpuff Girls, the decrepitly old Captain Righteous and Lefty are brought out of retirement because of their reputation in the past of being the only ones able to stop the Ministry of Pain. The Ministry themselves are also decrepitly old and have gone senile. They could have easily been stopped by the Powerpuffs, though Blossom insists that Righteous and Lefty be allowed to do it because the girls needed to respect their elders.
 * Wing Commander Academy: In one episode, the Tiger's Claw is attacked while most of her fighter wing is away. Because his remaining pilots are badly outnumbered, Commodore Tolwyn decides to climb into a fighter to personally take part in the fighting.
 * Also Inverted in at least one episode, where Tolwyn has Maverick stay aboard the Claw and supervise from the bridge while the rest of the fighter wing goes to fight the Kilrathi, in order to teach the cadet what it means to be in command, knowing that others might die following your orders.